TECHNICAL FIELD
[0002] The present invention relates to fibroblast growth factor receptor (FGFR) extracellular
domains (ECDs) that have been engineered to exhibit decreased tissue binding by increasing
the number of acidic amino acid residues within the D1-D2 linker region. The invention
further relates to polypeptide and polynucleotide sequences, vectors, host cells,
compositions, and kits comprising or encoding such molecules. The invention also relates
to methods of making and using FGFR ECD acidic region muteins to treat proliferative
disorders, including cancer, disorders of angiogenesis, and macular degeneration.
BACKGROUND ART
[0003] Fibroblast growth factors (FGFs) and their receptors (FGFRs) are a highly conserved
group of proteins with instrumental roles in angiogenesis, vasculogenesis, and wound
healing, as well as in tissue patterning and limb formation in embryonic development.
FGFs and FGFRs affect cell migration, proliferation, and survival, providing wide-ranging
impacts on health and disease.
[0004] The FGFR family comprises four major types of receptors, FGFR1, FGFR2, FGFR3, and
FGFR4. These receptors are transmembrane proteins having an extracellular domain (ECD),
a transmembrane domain, and an intracytoplasmic tyrosine kinase domain. Each of the
extracellular domains contains either two or three immunoglobulin (Ig) domains. When
there are three Ig domains, they are referred to as D1, D2, and D3. Receptors having
two Ig domains typically lack D1. An acidic motif, called the acid box, is located
in the linker region between D1 and D2 in the FGFR extracellular domain. The D2 domain
of FGFRs contains a heparin binding site. FGFR4 also contains a heparin binding site
in D1. The acid box is believed to interact with the heparin binding site in the D2
domain. Furthermore, it has been shown that the FGFR1 and FGFR3 D 1 domains are capable
of interacting with the D2 and D3 domains. It has been hypothesized that the FGFR1
acid box-mediated interactions with the D2 domain, and the FGFR1 D1 domain-mediated
interactions with the D2 and D3 domains play an autoinhibitory role that prevents
receptor oligomerization in the absence of FGF ligand. Finally, extracellular FGFR
activation by FGF ligand binding to an FGFR initiates a cascade of signaling events
inside the cell, beginning with oligomerization of the receptor and activation of
receptor tyrosine kinase activity.
[0005] To date, there are 22 known FGFs, each with the capacity to bind one or more FGFRs.
See, e.g., Zhang et al., J. Biol. Chem. 281:15, 694-15,700 (2006). Several FGFs can bind to and activate each of one or more FGFRs, often with large
differences in their affinities for the different FGFRs. Heparin sulfate proteoglycan
("heparin") is required for the binding of FGFs to FGFRs under certain circumstances.
See, e.g., Ornitz et al., Mol. Cell Biol. 12:240 (1992). For example, the mitogenic response to FGF2 (also known as basic FGF (bFGF)) mediated
by FGFR1 has been shown to depend on the presence of heparin.
See, e.g.,
Ornitz et al., Mol. Cell Biol. 12:240 (1992).
SUMMARY
[0007] The FGFR4 extracellular domain ("ECD") binds with high affinity to FGF2 and FGF 19
ligands, among others. By using the FGFR4 ECD as a 'ligand trap' to bind, for example,
free FGF2 and FGF 19, one may effectively treat proliferative disorders, including
cancer, disorders of angiogenesis, and macular degeneration. The present invention
provides a polypeptide comprising an FGFR4 extracellular domain (ECD) acidic region
mutein, wherein the FGFR4 ECD acidic region mutein is an FGFR4 ECD acidic region chimera,
wherein the FGFR4 ECD acidic region mutein has a greater number of acidic residues
in the D1-D2 linker region than wild-type FGFR4 ECD, wherein the FGFR4 ECD acidic
region chimera selected from an FGFR4 ECD D1-D2 linker chimera, an FGFR4 ECD exon
4 chimera, an FGFR4 ECD acid box chimera, an FGFR4 ECD long acid box chimera, and
an FGFR4 ECD short acid box chimera, and wherein the FGFR4 ECD acidic region mutein
exhibits decreased extracellular matrix (ECM) binding, decreased tissue binding, and/or
increased bioavailability relative to a parental FGFR4 ECD. The invention further
provides a polypeptide comprising an FGFR4 extracellular domain (ECD) acidic region
mutein, wherein the FGFR4 ECD acidic region mutein is an FGFR4 ECD long acid box variant,
wherein the number of acidic residues in the FGFR4 long acid box is at least seven,
wherein the FGFR4 ECD acidic region mutein exhibits decreased extracellular matrix
(ECM) binding, decreased tissue binding, and/or increased bioavailability compared
with wild-type FGFR4 ECD, and wherein: a) at least two non-acidic residues within
the long acid box of the FGFR4 ECD are each independently replaced with an acidic
residue selected from Glu (E) and Asp (D); b)
at least three non-acidic residues within the long acid box of the FGFR4 ECD are each
independently replaced with an acidic residue selected from Glu (E) and Asp (D); c)
at least four non-acidic residues within the long acid box of the FGFR4 ECD are each
independently replaced with an acidic residue selected from Glu (E) and Asp (D); d)
at least one acidic residue is inserted between amino acids 103 and 104 of SEQ ID
NOs: 1 and 2; e) two acidic residues are inserted between amino acids 103 and 104
of SEQ ID NOs: 1 and 2; f) FGFR4 ECD residues 104 to 114 (SEQ ID NO: 145) are replaced
with FGFR1 ECD residues 106 to 117 (SEQ ID NO: 149); g) FGFR4 ECD residues 104 to
114 (SEQ ID NO: 145) are replaced with FGFR1 ECD residues 107 to 117 (SEQ ID NO: 150);
h) FGFR4 ECD residues 104 to 110 (SEQ ID NO: 146) are replaced with FGFR1 ECD residues
105-113 (SEQ ID NO: 151); i) FGFR4 ECD residues 113 to 116 (SEQ ID NO: 147) are replaced
with FGFR1 ECD residues 116-119 (SEQ ID NO: 152); j) FGFR4 ECD residues 109 to 113
(SEQ ID NO: 148) are replaced with FGFR1 ECD residues 112-116 (SEQ ID NO: 153); or
k) the FGFR4 ECD long acid box variant comprises an amino acid sequence selected from
SEQ ID NOs: 111 to 119.
[0008] The invention is defined in the accompanying claims.
[0009] Experiments using purified Fc fusions of the wild-type FGFR4 ECD ("FGFR4 ECD Fc fusions")
showed that they exhibited poor bioavailability and a short serum half-life, which
is at least partially due to excessive tissue binding, when administered to mice using
intravenous (IV) methods.
See FIG. 4 and Table 5. In contrast, Fc fusions of the FGFR1 ECD exhibited higher bioavailability and serum
half-life. Furthermore, the FGFR4 ECD Fc fusions exhibited high levels of
in vitro binding to extracellular matrix (ECM) components, whereas Fc fusions of the FGFR1,
FGFR2, or FGFR3 ECD showed minimal or undetectable levels of ECM binding.
See FIG. 5.
[0010] As noted above, the FGFRs typically contain an acidic motif, called an acid box,
between the D1 and D2 domains. The D1 domain and the D1-D2 linker region, which contains
the acid box, are more divergent than the D2 and D3 domains between FGFR4 and the
other three FGFRs. Further, the FGFR1, FGFR2, and FGFR3 acid boxes all contain a greater
number of acidic amino acid residues than the FGFR4 acid box.
See FIGs. 11A, 11B, and 11C, respectively. Based on experiments described herein, we hypothesize that the relatively
"weak" FGFR4 acid box, which contains fewer acidic amino acid residues than the FGFR1,
FGFR2, and FGFR3 acid boxes, may be less effective at preventing tissue binding, and
may therefore be responsible for the greater ECM binding of the FGFR4 ECD Fc fusions
observed
in vitro.
[0011] We have engineered FGFR4 ECDs, called FGFR4 ECD acidic region muteins, that have
an increase in the total number of acidic residues within the D1-D2 linker and thus
a "stronger" acid box region to reduce ECM binding and potentially reduce tissue binding
in vivo and to increase the bioavailability of FGFR4 ECD fusion proteins. We have discovered
that FGFR4 ECD acidic region muteins that contain an increased number of acidic residues
within the D1-D2 linker exhibit decreased ECM binding. We have also discovered that
certain FGFR4 ECD acidic region muteins exhibit decreased tissue binding and increased
bioavailability. Thus, by increasing the total number of acidic residues within the
D1-D2 linker, thus "strengthening" the FGFR4 acid box, we have engineered FGFR4 ECD
acidic region muteins with improved properties, including decreased ECM binding and
decreased tissue binding, which can in turn lead to increased bioavailability of FGFR4
ECD fusion proteins.
[0012] In one approach for generating "stronger" FGFR4 ECD acidic region muteins, we have
replaced certain non-acidic amino acid residues with acidic amino acid residues, such
that the total number of acidic residues within the FGFR4 ECD long acid box is increased
relative to the wild-type FGFR4 ECD long acid box. This class of FGFR4 ECD acidic
region muteins is referred to herein as "FGFR4 ECD long acid box variants." We discovered
that FGFR4 ECD long acid box variants that comprise two more acidic amino acid residues
than the wild-type FGFR4 ECD long acid box exhibited decreased ECM binding.
See FIG. 14. FGFR4 ECD long acid box variants that contained four more acidic amino acid residues
in the long acid box exhibited even further decreased ECM binding.
See id.
[0013] In another approach for generating "stronger" FGFR4 ECD acidic region muteins, we
have replaced all or portions of the D1-D2 linker region of FGFR4 with all or portions
of the D1-D2 linker region of FGFR1, FGFR2, or FGFR3 to generate polypeptides in a
class of FGFR4 ECD acidic region muteins referred to herein as "FGFR4 ECD acidic region
chimeras." FGFR4 ECD acidic region chimeras include FGFR4 ECD, D1-D2 linker chimeras,
FGFR4 ECD exon 4 chimeras, FGFR4 ECD acid box chimeras, FGFR4 ECD long acid box chimeras,
and FGFR4 ECD short acid box chimeras. We found that at least certain FGFR4 ECD D1-D2
linker chimeras, FGFR4 ECD exon 4 chimeras, and FGFR4 ECD acid box chimeras, retained
the ability to bind to both FGF2 and FGF19, but showed decreased levels of ECM binding
in vitro when compared to a parental FGFR4 ECD Fc fusion.
See Tables 3 and 4, and
FIGs. 6 and 12. Further, the FGFR4 ECD acidic region chimeras showed decreased binding to the surface
of hepatocytes when compared to a parental FGFR4 ECD Fc fusion.
See FIG. 7. In vitro ECM binding by an FGFR4 acidic region chimera was further reduced by introducing
an N-glycan mutation either adjacent to the amino-terminus of the FGFR4 ECD D1-D2
linker or in the D2 heparin binding site.
See FIG. 15.
[0014] In
in vivo studies, an FGFR4 ECD acidic region mutein exhibited substantially improved bioavailability
and serum half-life relative to a parental FGFR4 ECD Fc fusion.
See FIG. 8. Mice injected with the FGFR4 ECD acidic region mutein showed a statistically significant
reduction in tumor burden in certain tumor models when compared to a control group,
showing that the FGFR4 ECD acidic region muteins possess a similar anti-tumor activity
as FGFR4 ECDs administered
in vivo. See FIG. 9. The FGFR4 ECD acidic region muteins may therefore be used, e.g., to treat proliferative
disorders, including cancer, disorders of angiogenesis, and macular degeneration.
[0015] Both the FGFR2 ECD-Fc and FGFR3 BCD-Fc fusion proteins showed significantly lower
levels of ECM binding
in vitro than a parental FGFR4 ECD-Fc, however they showed slightly higher levels of ECM binding
than an FGFR1 ECD-Fc fusion protein at higher protein concentrations.
See FIG. 5. Although the FGFR2 and FGFR3 acid boxes contain a greater number of acidic amino
acid residues than the FGFR4 acid box, they both contain fewer acidic amino acid residues
than the FGFR1 acid box.
See FIGs. 11D and
11E, respectively.
In vitro ECM binding experiments showed that FGFR2 and FGFR3 ECD acidic region muteins in
which the total number of acidic residues within the FGFR2 and FGFR3 long acid boxes
was increased exhibited decreased ECM binding relative to the parental FGFR2 and FGFR3
ECDs.
See FIGs. 17A and 17B, respectively.
[0016] In certain embodiments, FGFR1, FGFR2, and FGFR3 ECDs may be engineered to have a
decrease in the total number of acidic residues within the D1-D2 linker, and thus
a "weaker" acid box to increase tissue binding
in vivo and to decrease the bioavailalbility of the FGFR1, FGFR2, and FGFR3 ECD fusion proteins.
Such "weakened" FGFR1, FGFR2, and FGFR3 ECDs may be useful, for example, when delivered
locally, to prevent toxicity and/or side effects that might occur with systemic administration.
[0017] In certain embodiments, a polypeptide comprising an FGFR4 ECD acidic region mutein
is provided. In certain embodiments, an isolated polypeptide comprising an FGFR4 ECD
acidic region mutein is provided. In certain embodiments, an FGFR4 ECD acidic region
mutein is an FGFR4 ECD D1-D2 linker chimera. In certain embodiments, the FGFR4 ECD
D1-D2 linker chimera comprises a D1-D2 linker selected from an FGFR1 D1-D2 linker,
an FGFR2 D1-D2 linker, and an FGFR3 D1-D2 linker, in place of the FGFR4 D1-D2 linker.
In certain embodiments, the FGFR4 ECD D1-D2 linker chimera comprises an amino acid
sequence selected from SEQ ID NOs: 22, 26, 28, and 32, in place of an FGFR4 D1-D2
linker selected from SEQ ID NOs: 16 and 17. In certain embodiments, the FGFR4 ECD
D1-D2 linker chimera comprises an amino acid sequence selected from SEQ ID NOs: 35
to 38.
[0018] In certain embodiments, an FGFR4 ECD acidic region mutein is an FGFR4 ECD exon 4
chimera. In certain embodiments, the FGFR4 ECD exon 4 chimera comprises an exon 4
selected from an FGFR1 exon 4, an FGFR2 exon 4, and an FGFR3 exon 4, in place of the
FGFR4 exon 4. In certain embodiments, the FGFR4 ECD exon 4 chimera comprises an amino
acid sequence selected from SEQ ID NOs: 23, 92, 29, and 33, in place of an FGFR4 D1-D2
linker selected from SEQ ID NOs: 18 and 19. In certain embodiments, the FGFR4 ECD
exon 4 chimera comprises an amino acid sequence selected from SEQ ID NOs: 39 to 42.
[0019] In certain embodiments, an FGFR4 ECD acidic region mutein is an FGFR4 ECD acid box
chimera. In certain embodiments, the FGFR4 ECD acid box chimera comprises an acid
box selected from the FGFR1 acid box, the FGFR2 acid box, and the FGFR3 acid box,
in place of the FGFR4 acid box. In certain embodiments, the FGFR4 ECD acid box chimera
comprises an amino acid sequence selected from SEQ ID NOs: 24, 30, and 34 in place
of the FGFR4 acid box having an amino acid sequence of SEQ ID NO: 20. In certain embodiments,
an FGFR4 ECD acid box chimera comprises an acid box region selected from an FGFR1
acid box region, an FGFR2 acid box region, and an FGFR3 acid box region, in place
of the FGFR4 acid box. In certain embodiments, the FGFR4 ECD acid box chimera comprises
an amino acid sequence selected from SEQ ID NOs: 56 to 65, in place of the FGFR4 acid
box having an amino acid sequence of SEQ ID NO: 20. In certain embodiments, the FGFR4
ECD acid box chimera comprises an acid box region selected from an FGFR1 acid box
region, an FGFR2 acid box region, and an FGFR3 acid box region, in place of an FGFR4
acid box region. In certain embodiments, the FGFR4 ECD acid box chimera comprises
an amino acid sequence selected from SEQ ID NOs: 56 to 65, in place of an FGFR4 acid
box region having an amino acid sequence selected from SEQ ID NOs: 46 to 55. In certain
embodiments, the FGFR4 ECD acid box chimera comprises an FGFR1 acid box region having
the amino acid sequence of SEQ ID NO: 56 in place of an FGFR4 acid box region having
the amino acid sequence of SEQ ID NO: 51. In certain embodiments, the FGFR4 ECD acid
box chimera comprises an acid box selected from the FGFR1 acid box, the FGFR2 acid
box, and the FGFR3 acid box, in place of an FGFR4 acid box region. In certain embodiments,
the FGFR4 ECD acid box chimera comprises an amino acid sequence selected from SEQ
ID NOs: 24, 30, and 34 in place of an FGFR4 acid box region having an amino acid sequence
selected from SEQ ID NOs: 46 to 55. In certain embodiments, the FGFR4 ECD acid box
chimera comprises an amino acid sequence selected from SEQ ID NOs: 43 to 45 and 157.
[0020] In certain embodiments, an FGFR4 ECD acidic region chimera is an FGFR4 ECD long acid
box chimera. In certain embodiments, the FGFR4 ECD long acid box chimera comprises
a long acid box selected from an FGFR1 long acid box, an FGFR2 long acid box, and
an FGFR3 long acid box, in place of the FGFR4 long acid box. In certain embodiments,
the FGFR4 long acid box chimera comprises an amino acid sequence selected from SEQ
ID NOs: 98 to 100, in place of an FGFR4 long acid box selected from SEQ ID NOs: 96
and 97. In certain embodiments, the FGFR4 long acid box chimera comprises an amino
acid sequence selected from SEQ ID NOs: 105 to 107.
[0021] In certain embodiments, an FGFR4 ECD acidic region mutein is an FGFR4 ECD short acid
box chimera. In certain embodiments, the FGFR4 ECD short acid box chimera comprises
a short acid box selected from an FGFR1 short acid box, an FGFR2 short acid box, and
an FGFR3 short acid box, in place of the FGFR4 short acid box. In certain embodiments,
the FGFR4 ECD short acid box chimera comprises an amino acid sequence selected from
SEQ NOs: 102 to 104, in place of an FGFR4 short acid box having an amino acid sequence
of SEQ ID NO: 101. In certain embodiments, the FGFR4 ECD short acid box chimera comprises
an amino acid sequence selected from SEQ ID NOs: 108 to 110.
[0022] In certain embodiments, the FGFR4 ECD acidic region mutein is an FGFR4 ECD long acid
box variant. In certain embodiments, the the FGFR4 ECD long acid box variant comprises
a variant of the FGFR4 ECD that has an increased number of acidic amino acid residues
in the long acid box relative to the FGFR4 wild-type long acid box. In certain such
embodiments, at least two, three, or four non-acidic residues within the long acid
box of the FGFR4 ECD are each independently replaced with an acidic residue selected
from Glu (E) and Asp (D). In certain such embodiments, at least one acidic residue
is inserted between amino acids 103 and 104 of SEQ ID NOs: 1 and 2. In certain embodiments,
two acidic residues are inserted between amino acids 103 and 104 of SEQ ID NOs: 1
and 2. In certain such embodiments, the number of acidic residues in the FGFR4 long
acid box is at least seven. In certain such embodiments, FGFR4 ECD residues 104 to
114 (SEQ ID NO: 145) are replaced with FGFR1 ECD residues 106 to 117 (SEQ ID NO: 149);
FGFR4 ECD residues 104 to 114 (SEQ ID NO: 145) are replaced with FGFR1 ECD residues
107 to 117 (SEQ ID NO: 150); FGFR4 ECD residues 104 to 110 (SEQ ID NO: 146) are replaced
with FGFR1 ECD residues 105-113 (SEQ ID NO: 151); FGFR4 ECD residues 113 to 116 (SEQ
ID NO: 147) are replaced with FGFR1 ECD residues 116-119 (SEQ ID NO: 152); or FGFR4
ECD residues 109 to 113 (SEQ NO: 148) are replaced with FGFR1 ECD residues 112-116
(SEQ ID NO: 153). In certain such embodiments, FGFR4 ECD residues 104 to 114 (SEQ
ID NO: 145) are replaced with FGFR1 ECD residues 106 to 117 (SEQ ID NO: 149); FGFR4
ECD residues 104 to 114 (SEQ ID NO: 145) are replaced with FGFR1 ECD residues 107
to 117 (SEQ ID NO: 150); FGFR4 ECD residues 104 to 110 (SEQ ID NO: 146) are replaced
with FGFR1 ECD residues 105-113 (SEQ ID NO: 151); FGFR4 ECD residues 113 to 116 (SEQ
ID NO: 147) are replaced with FGFR1 ECD residues 116-119 (SEQ ID NO: 152); or FGFR4
ECD residues 109 to 113 (SEQ ID NO: 148) are replaced with FGFR1 ECD residues 112-116
(SEQ ID NO: 153).
[0023] In certain embodiments, an FGFR4 ECD fusion molecule comprising an FGFR4 ECD acidic
region mutein and a fusion partner is provided. In certain embodiments, an isolated
FGFR4 ECD fusion molecule comprising an FGFR4 ECD acidic region mutein and a fusion
partner is provided. In certain embodiments, an FGFR4 ECD fusion molecule comprising
an amino acid sequence selected from SEQ ID NOs: 35 to 45, 105 to 121, and 157 is
provided. In certain embodiments, an isolated FGFR4 ECD fusion molecule comprising
an amino acid sequence selected from SEQ ID NOs: 35 to 45, 105 to 121, and 157 is
provided. In certain embodiments, an FGFR4 ECD fusion molecule comprising the amino
acid sequence of SEQ ID NO: 35, is provided. In certain embodiments, an isolated FGFR4
ECD fusion molecule comprising the amino acid sequence of SEQ ID NO: 35, is provided.
In certain embodiments, the fusion partner is selected from Fc, albumin, and polyethylene
glycol. In certain embodiments, the fusion partner is Fc. In certain embodiments,
an FGFR4 ECD fusion molecule comprising an amino acid sequence selected from SEQ ID
NOs: 86 to 88, 124 to 140, 143, 144, and 158 is provided. In certain embodiments,
an isolated FGFR4 ECD fusion molecule comprising an amino acid sequence selected from
SEQ ID NOs: 86 to 88, 124 to 140, 143, 144, and 158 is provided. In certain embodiments,
an FGFR4 ECD fusion molecule comprising the amino acid sequence of SEQ ID NO: 86 is
provided. In certain embodiments, an isolated FGFR4 ECD fusion molecule comprising
the amino acid sequence of SEQ ID NO: 86 is provided. In certain embodiments, an FGFR4
ECD fusion molecule consisting of the amino acid sequence of SEQ ID NO: 86 is provided.
In certain embodiments, an isolated FGFR4 ECD fusion molecule consisting of the amino
acid sequence of SEQ ID NO: 86 is provided.
[0024] In certain embodiments, a pharmaceutical composition comprising an FGFR4 ECD acidic
region mutein and a pharmaceutically acceptable carrier is provided. In certain embodiments,
a polynucleotide comprising a nucleic acid sequence that encodes an FGFR4 ECD acidic
region mutein is provided.
[0025] In certain embodiments, a method of treating an angiogenic disorder in a patient
comprising administering to the patient a pharmaceutical composition comprising an
FGFR4 ECD acidic region mutein is provided. In certain embodiments, a method of treating
cancer in a patient comprising administering to the patient a pharmaceutical composition
comprising an FGFR4 ECD acidic region mutein is provided. In certain embodiments,
the cancer is selected from colon, liver, lung, breast, and prostate cancers. In certain
embodiments, a method of treating macular degeneration in a patient comprising administering
to the patient a pharmaceutical composition comprising an FGFR4 ECD acidic region
mutein is provided.
[0026] In certain embodiments, the FGFR4 acidic region mutein comprises at least one point
mutation that inhibits glycosylation. In certain embodiments, the at least one point
mutation that inhibits glycosylation is selected from N91A, N156A, N237A, N269A, N290A,
and N301A. In certain embodiments, the FGFR4 acidic region mutein comprises an amino
acid sequence selected from SEQ ID NOs: 120, 121, and 168.
[0027] In certain embodiments, an FGFR2 ECD acidic region mutein is provided. In certain
embodiments, the FGFR2 ECD acidic region mutein is an FGFR2 ECD short acid box chimera.
In certain embodiments, the FGFR2 ECD short acid box chimera comprises at least the
FGFR1 short acid box in place of at least the FGFR2 short acid box. In certain such
embodiments, FGFR2 ECD residues 111 to 118 (SEQ ID NO: 155) are replaced with FGFR1
ECD residues 105 to 112 (SEQ ID NO: 154). In certain embodiments, the FGFR2 ECD short
acid box chimera comprises the amino acid sequence of SEQ ID NO: 122.
[0028] In certain embodiments, an FGFR3 ECD acidic region mutein is provided. In certain
embodiments, the FGFR3 ECD acidic region mutein is an FGFR3 ECD short acid box chimera.
In certain embodiments, the FGFR3 ECD short acid box chimera comprises at least the
FGFR1 short acid box in place of at least the FGFR3 short acid box. In certain such
embodiments, FGFR3 ECD residues 110 to 117 (SEQ ID NO: 156) are replaced with FGFR1
ECD residues 105 to 112 (SEQ ID NO: 154). In certain embodiments, the FGFR3 ECD short
acid box chimera comprises the amino acid sequence of SEQ ID NO: 123.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029]
FIG. 1 shows the extracellular domain (ECD) amino acid sequence of FGFR4 with a 17 amino
acid C-terminal deletion, which was fused to an Fc domain in the parental FGFR4 ECD-Fc
(also referred to herein as "R4Mut4"). The amino acid sequence in Figure 1 includes
the signal peptide, which is cleaved in the mature fusion protein. The numbers refer
to the amino acid position, and certain domains within the ECD are illustrated in
gray above the amino acid numbers. The amino acid positions within the signal peptide
are given negative values because they are cleaved in the mature fusion protein. The
first amino acid residue of the mature fusion protein is designated as amino acid
position 1. The linker between the first and second Ig domains (referred to herein
interchangeably, as the "linker domain," "linker region," "D1-D2 linker," and "D1-D2
linker region") is illustrated in a darker gray.
FIG. 2 shows a sequence alignment of the linker domains from FGFR1 and FGFR4 and the boundaries
and sequence of the swapped regions in the three variants, called FGFR4ECD(ABMut1
: delta17)-Fc (ABMut1), FGFR4ECD(ABMut2: delta17)-Fc (ABMut2), and FGFR4ECD(ABMut3:
delta17)-Fc (ABMut3). Acidic residues within the D1-D2 linker are indicated with underlining
and bold font.
FIG. 3 shows the binding of R1Mut4, three different preparations of R4Mut4, R4Mut4 plus
heparin, and an IgG control to hepatocytes, detected by flow cytometry, as described
in Example 5. The number of cells (counts) is shown on the Y-axis, and the X-axis
shows the relative fluorescent signal, in log units.
FIG. 4 is a graphical representation of the plasma concentration (ng/ml) in mice of R4Mut4,
administered with and without heparin, as described in Example 6. The plasma concentration
is shown on the Y-axis, and was determined using an FGF2-binding ELISA. The X-axis
shows the time following administration. The dashed line represents the lower limit
of reproducible R4Mut4 detectability in the ELISA (approximately 156 ng/ml). Each
data point represents the average from 5 animals, with the error bars representing
the standard error of the mean.
FIG. 5 shows the binding of commercially-available FGFR1 ECD-Fc, FGFR2 ECD-Fc, FGFR3 ECD-Fc,
and FGFR4 ECD-Fc to Matrigel plates, as described in Example 7. The X-axis shows the
concentration of the Fc fusion proteins and the Y-axis shows the absorbance at 450
nm following incubation of the bound Fc fusion protein with OPD substrate. All binding
reactions were carried out in triplicate and the data points represent the average
values obtained.
FIG. 6 shows the binding of R1Mut4, R4Mut4, and FGFR4 ECD acidic region chimeras ABMut1,
ABMut2, and ABMut3 to Matrigel plates, as described in Example 9. The X-axis shows
the concentration of the Fc fusion proteins and the Y-axis shows the absorbance at
450 nm following incubation of the bound Fc fusion protein with OPD substrate. All
binding reactions were carried out in triplicate and the data points represent the
average value obtained.
FIG. 7 shows the binding of R1Mut4, R4Mut4, FGFR4 ECD acidic region chimeras ABMut1, ABMut2,
and ABMut3, and an IgG control, to hepatocytes detected by flow cytometry, as described
in Example 10. The number of cells (counts) is shown on the Y-axis, and the X-axis
shows the relative fluorescent signal, in log units.
FIG. 8 is a graphical representation of the plasma concentrations (ng/ml) of R4Mut4 and
ABMut1 following their administration to mice, as described in Example 11. The plasma
concentrations are shown on the Y-axis, and were determined using an FGF2-binding
ELISA. The X-axis shows the time following administration. The dashed line represents
the lower limit of reproducible R4Mut4 detectability in the ELISA (approximately 8
ng/ml). Data from five animals for each time point are included in the figure.
FIG. 9 shows the results of the xenograft experiment described in Example 12. Mice were
inoculated with tumor cells, and tumor growth was measured after administration of
R4Mut4, ABMut1, or vehicle alone. The tumor size is shown on the Y-axis, and the number
of days following tumor inoculation is shown on the X-axis. The dosing schdule for
each treatment group is shown in Table 9, and the p-values of each treatment group
at days 14 and 21 are shown in Table 10.
FIG. 10 shows the amino acid sequence of the FGFR4 ECD acidic region, along with the locations
of certain regions within the FGFR4 ECD acidic region, as defined herein.
FIG. 11 shows amino acid sequence alignments between (A) the FGFR4 ECD acidic region and
the FGFR1 ECD acidic region, (B) the FGFR4 ECD acidic region and the FGFR2 ECD acidic
region, (C) the FGFR4 ECD acidic region and the FGFR3 ECD acidic region, (D) the FGFR1
ECD acidic region and the FGFR2 ECD acidic region, and (E) the FGFR1 ECD acidic region
and the FGFR3 ECD acidic region.
FIG. 12 shows the binding of high concentrations of R4Mut4 and ABMut1 fusion proteins expressed
in CHO or 293-T cells to Matrigel plates, as described in Example 13. The X-axis shows
the concentration of the Fc fusion proteins and the Y-axis shows the absorbance at
450 nm following incubation of the bound Fc fusion protein with OPD substrate.
FIG. 13 shows the binding of R1Mut4, R4Mut4, ABMut1, R4Mut4(N104D), R4Mut4(P109D), R4Mut4(R113E),
and R4Mut4(S116E) fusion proteins to Matrigel plates, as described in Example 14.
The X-axis shows the concentration of the Fc fusion proteins and the Y-axis shows
the absorbance at 450 nm following incubation of the bound Fc fusion protein with
OPD substrate.
FIG. 14 shows the binding of R1Mut4, R4Mut4, ABMut1, R4(104-114):R1(106-117), R4(104-114):R1(107-117),
R4(104-110):R1(105-113), R4(113-116):R1(116-119), and R4(109-113):R1(112-116) fusion
proteins to Matrigel plates, as described in Example 15. The X-axis shows the concentration
of the Fc fusion proteins and the Y-axis shows the absorbance at 450 nm following
incubation of the bound Fc fusion protein with OPD substrate.
FIG. 15 shows the binding of R4Mut4, ABMut1, ABMut1(N91A), and ABMut1(N159A) fusion proteins
to Matrigel plates, as described in Example 16. The X-axis shows the concentration
of the Fc fusion proteins and the Y-axis shows the absorbance at 450 nm following
incubation of the bound Fc fusion protein with OPD substrate.
FIG. 16 shows the binding of the R1Mut4, R4Mut4, ABMut1, R4(D1-D2):R2(D1-D2), and R4(D1-D2):R3(D1-D2)
fusion proteins to Matrigel plates, as described in Example 17. The X-axis shows the
concentration of the Fc fusion proteins and the Y-axis shows the absorbance at 450
nm following incubation of the bound Fc fusion protein with OPD substrate.
FIG. 17 shows the binding of FGFR2 ECD-Fc, FGFR3 ECD-Fc, R2(111-118):R1(105-112), and R3(110-117):R1(105-112)
fusion proteins to Matrigel plates, as described in Example 18. The X-axis shows the
concentration of the Fc fusion proteins and the Y-axis shows the absorbance at 450
nm following incubation of the bound Fc fusion protein with OPD substrate.
DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS
[0030] The section headings used herein are for organizational purposes only and are not
to be construed as limiting the subject matter described.
Definitions
[0031] Unless otherwise defined, scientific and technical terms used in connection with
the present invention shall have the meanings that are commonly understood by those
of ordinary skill in the art. Further, unless otherwise required by context, singular
terms shall include pluralities and plural terms shall include the singular.
[0032] Certain techniques used in connection with recombinant DNA, oligonucleotide synthesis,
tissue culture and transformation (e.g., electroporation, lipofection), enzymatic
reactions, and purification techniques are known in the art. Many such techniques
and procedures are described, e.g., in
Sambrook et al. Molecular Cloning: A Laboratory Manual (2d ed., Cold Spring Harbor
Laboratory Press, Cold Spring Harbor, N.Y. (1989)), among other places. In addition, certain techniques for chemical syntheses, chemical
analyses, pharmaceutical preparation, formulation, and delivery, and treatment of
patients are also known in the art.
[0033] In this application, the use of "or" means "and/or" unless stated otherwise. In the
context of a multiple dependent claim, the use of "or" refers back to more than one
preceding independent or dependent claim in the alternative only. Also, terms such
as "element" or "component" encompass both elements and components comprising one
unit and elements and components that comprise more than one subunit unless specifically
stated otherwise.
[0034] As utilized in accordance with the present disclosure, the following terms, unless
otherwise indicated, shall be understood to have the following meanings:
[0035] The terms
"nucleic acid molecule" and
"polynucleotide" may be used interchangeably, and refer to a polymer of nucleotides. Such polymers
of nucleotides may contain natural and/or non-natural nucleotides, and include, but
are not limited to, DNA, RNA, and PNA.
[0036] The terms
"polypeptide" and
"protein" are used interchangeably, and refer to a polymer of amino acid residues. Such polymers
of amino acid residues may contain natural and/or non-natural amino acid residues,
and include, but are not limited to, peptides, oligopeptides, dimers, trimers, and
multimers of amino acid residues. The terms "polypeptide" and "protein" include natural
and non-natural amino acid sequences, and both full-length proteins and fragments
thereof. Those terms also include post-translationally modified polypeptides and proteins,
including, for example, glycosylated, sialylated, acetylated, and/or phosphorylated
polypeptides and proteins.
[0037] The terms
"acidic amino acid," "acidic amino acid residue," and
"acidic residue" are used interchangeably herein and refer to an amino acid residue that
is negatively charged at physiological pH. Acidic amino acids include, but are not
limited to, aspartic acid (Asp, D) and glutamic acid (Glu, E).
[0038] The terms
"non-acidic amino acid," "non-acidic amino acid residue," and
"non-acidic residue" are used interchangeably and refer to an amino acid residue that is not negatively
charged at physiological pH.
[0039] The terms
"FGFR extracellular domain" and
"FGFR ECD" include FGFR1 ECD, FGFR2 ECDs, FGFR3 ECDs, and FGFR4 ECDS, as defined herein.
[0040] The terms
"FGFR1 extracellular domain" and
"FGFR1 ECD" include native FGFR1 ECDs, FGFR1 ECD fragments, and FGFR1 ECD variants. As used herein,
the term
"native FGFR1 ECD" refers to an FGFR1 ECD having an amino acid sequence selected from SEQ ID NOs: 21
and 25. As used herein, the term
"FGFR1 ECD fragment" refers a polypeptide having an amino acid sequence selected from SEQ ID NOs: 21 and
25, but wherein amino acid residues have been deleted from the amino-terminus and/or
carboxy-terminus, wherein the fragments are capable of binding to FGF2. As used herein,
the term
"FGFR1 ECD variants" refers to variants of the portion of the FGFR1 polypeptide that extends into the
extracellular space and variants of fragments thereof that comprise D1, D2, and D3,
wherein the variants are capable of binding to FGF2. Such variants may contain amino
acid additions, deletions, and substitutions, provided that the FGFR1 ECD variants
remain capable of ligand binding.
[0041] In certain embodiments, an FGFR1 ECD lacks a signal peptide. In certain embodiments,
an FGFR1 ECD includes at least one signal peptide, which may be selected from a native
FGFR1 signal peptide and/or a heterologous signal peptide.
[0042] The terms
"FGFR2 extracellular domain" and
"FGFR2 ECD" include native FGFR12 ECDs, FGFR2 ECD fragments, and FGFR2 ECD variants. As used
herein, the term
"native FGFR2 ECD" refers to an FGFR2 ECD having an amino acid sequence of SEQ ID NO: 27. As used herein,
the term
"FGFR2 ECD fragment" refers a polypeptide having an amino acid sequence selected from SEQ ID NO: 27, but
wherein amino acid residues have been deleted from the amino-terminus and/or carboxy-terminus,
wherein the fragments are capable of binding to FGF2. A non-limiting exemplary FGFR2
ECD fragment has the amino acid sequence of SEQ ID NO: 160, which corresponds to the
amino acid sequence of SEQ ID NO: 27, but with the last three carboxy-terminal amino
acid residues, YLE, deleted. As used herein, the term
"FGFR2 ECD variants" refers to variants of the portion of the FGFR2 polypeptide that extends into the
extracellular space and variants of fragments thereof that comprise D1, D2, and D3,
wherein the variants are capable of binding to FGF2. Such variants may contain amino
acid additions, deletions, and substitutions, provided that the FGFR2 ECD variant
remains capable of ligand binding. FGFR2 ECD variants may include amino acid substitutions
within the FGFR2 ECD that inhibit N-glycosylation, referred to interchangeably herein
as
"FGFR2 ECD glycosylation mutants" and
"FGFR2 ECD N-glycan mutants." In certain embodiments, at least one amino acid within the FGFR2 ECD is mutated to
prevent glycosylation at that site in the polypeptide. Non-limiting exemplary FGFR2
ECD amino acids that maybe glycosylated include N62, N102, N207, N220, N244, N276,
N297, and N310 in SEQ ID NO: 27. Non-limiting exemplary amino acid mutations in FGFR4
ECD glycosylation mutants include N62A, N102A, N207A, N220A, N244A, N276A, N297A,
and N310A in SEQ ID NO: 27.
[0043] In certain embodiments, an FGFR2 ECD lacks a signal peptide. In certain embodiments,
an FGFR2 ECD includes at least one signal peptide, which may be selected from a native
FGFR2 signal peptide and/or a heterologous signal peptide.
[0044] The terms
"FGFR3 extracellular domain" and
"FGFR3 ECD" include native FGFR3 ECDs, FGFR3 ECD fragments, and FGFR3 ECD variants. As used herein,
the term
"native FGFR3 ECD" refers to an FGFR3 ECD having an amino acid sequence of SEQ ID NO: 31. As used herein,
the term
"FGFR3 ECD fragment" refers a polypeptide having an amino acid sequence selected from SEQ ID NO: 31, but
wherein amino acid residues have been deleted from the amino-terminus and/or carboxy-terminus,
wherein the fragments are capable of binding to FGF2. A non-limiting exemplary FGFR3
ECD fragment has the amino acid sequence of SEQ ID NO: 161, which corresponds to the
amino acid sequence of SEQ ID NO: 31, but with the last three carboxy-terminal amino
acid residues, YAG, deleted. As used herein, the term
"FGFR3 ECD variants" refers to variants of the portion of the FGFR3 polypeptide that extends into the
extracellular space and variants of fragments thereof that comprise D1, D2, and D3,
wherein the variants are capable of binding to FGF2. Such variants may contain amino
acid additions, deletions, and substitutions, provided that the FGFR3 ECD variant
remains capable of ligand binding. FGFR3 ECD variants may include amino acid substitutions
within the FGFR3 ECD that inhibit N-glycosylation, referred to interchangeably herein
as
"FGFR3 ECD glycosylation mutants" and
"FGFR3 ECD N-glycan mutants." In certain embodiments, at least one amino acid within the FGFR3 ECD is mutated to
prevent glycosylation at that site in the polypeptide. Non-limiting exemplary FGFR3
ECD amino acids that may be glycosylated include N76, N203, N240, N272, N293, and
N306 in SEQ ID NO: 31. Non-limiting exemplary amino acid mutations in FGFR3 ECD glycosylation
mutants include N76A, N203A, N240A, N272A, N293A, and N306A in SEQ ID NO: 31.
[0045] In certain embodiments, an FGFR3 ECD lacks a signal peptide. In certain embodiments,
an FGFR3 ECD includes at least one signal peptide, which may be selected from a native
FGFR3 signal peptide and/or a heterologous signal peptide.
[0046] The terms
"FGFR4 extracellular domain" and
"FGFR4 ECD" include native FGFR4 ECDs, FGFR4 ECD fragments, and FGFR4 ECD variants. As used herein,
the term
"native FGFR4 ECD" refers to an FGFR4 ECD having an amino acid sequence selected from SEQ ID NOs: 1,
2, 3, and 93. As used herein, the term
"FGFR4 ECD fragment" refers a polypeptide having an amino acid sequence selected from SEQ ID NOs: 1, 2,
3, and 93, but wherein all or a portion of the sequence LEASEEVE (SEQ ID NO: 70) has
been deleted from the amino terminus and/or all or a portion of the sequence LPEEDPTWTAAAPEARYTD
(SEQ ID NO: 71) has been deleted from the carboxy terminus of the polypeptide, wherein
the fragments are capable of binding to FGF2 and/or FGF19. Non-limiting exemplary
FGFR4 ECD fragments have the amino acid sequences shown in SEQ ID NOs: 6 to 10 and
76 to 81. As used herein, the term
"FGFR4 ECD variants" refers to variants of the portion of the FGFR4 polypeptide that extends into the
extracellular space and variants of fragments thereof that comprise D1, D2, and D3,
wherein the variants are capable of binding to FGF2 and/or FGF19. Such variants may
contain amino acid additions, deletions, and substitutions, provided that the FGFR4
ECD variant remains capable of binding to FGF2 and/or FGF19 (see below for a discussion
of the structure/function relationship of FGFR extracellular domains).
[0047] FGFR4 ECD variants may include amino acid substitutions within the FGFR4 ECD that
inhibit N-glycosylation, referred to interchangeably herein as
"FGFR4 ECD glycosylation mutants" and
"FGFR4 ECD N-glycan mutants." In certain embodiments, one or more amino acids within the FGFR4 ECD are mutated
to prevent glycosylation at that site in the polypeptide. Non-limiting exemplary FGFR4
ECD amino acids that may be glycosylated include N91, N156, N237, N269, N290, and
N301 in SEQ ID NOs: 1 and 2. Non-limiting exemplary amino acid mutations in FGFR4
ECD glycosylation mutants include N91A, N156A, N237A, N269A, N290A, and N301A in SEQ
ID NOs: 1 and 2.
[0048] In certain embodiments, an FGFR4 ECD lacks a signal peptide. In certain embodiments,
an FGFR4 ECD includes at least one signal peptide, which may be selected from a native
FGFR4 signal peptide and/or a heterologous signal peptide.
[0049] The terms
"FGFR4 2Ig extracellular domain" and
"FGFR4 2Ig ECD" include FGFR4 2Ig ECDs, FGFR4 2Ig ECD fragments, and FGFR4 2Ig ECD variants. As used
herein, the term
"FGFR4 2Ig ECD" refers to a polypeptide comprising the acid box and domains D2 and D3 , wherein the
polypeptide has an amino acid sequence selected from SEQ ID NOs: 1, 2, 3, and 93,
but with at least a portion of D1 deleted. Exemplary FGFR4 2Ig ECDs have the amino
acid sequence of SEQ ID NO: 94. As used herein, the term
"FGFR4 2Ig ECD fragment" refers to an FGFR4 2Ig ECD polypeptide wherein all or a portion of the sequence LPEEDPTWTAAAPEARYTD
(SEQ ID NO: 71) has been deleted from the carboxy-terminus of the polypeptide. As
used herein, the term
"FGFR4 2Ig ECD variants" refers to variants of the FGFR4 2Ig ECDs and FGFR4 2Ig ECD fragments discussed above,
wherein the variants are capable of binding to FGF2 and/or FGF19. Such variants may
contain amino acid additions, deletions, and substitutions, provided that the FGFR4
2 Ig ECD variant remains capable of binding to FGF2 and/or FGF19 (see below for a
discussion of the structure/function relationship of FGFR extracellular domains).
[0050] An
"FGFR4 ECD D1-D2 linker chimera" refers to an FGFR4 ECD selected from native FGFR4 ECDs, FGFR4 ECD fragments, and
FGFR4 ECD variants, in which the linker region between immunoglobulin-like domain
I (D1) and immunoglobulin-like domain II (D2) (referred to herein interchangeably
as the "linker domain," "linker region," "D1-D2 linker," and "D1-D2 linker region")
has been replaced with the D1-D2 linker region from FGFR1, FGFR2, or FGFR3. The D1-D2
linker of the FGFR4 ECD has the sequence DSLTSSNDDEDPKSHRDPSNRHSYPQQ (SEQ ID NO: 16),
which is amino acids 98 to 124, inclusive, of SEQ ID NO: 1; or has the sequence DSLTSSNDDEDPKSHRDLSNRHSYPQQ
(SEQ ID NO: 17), which is amino acids 98 to 124, inclusive, of SEQ ID NO: 2. The D1-D2
linker of FGFR1 has the sequence DALPSSEDDDDDDDSSSEEKETDNTKPNPV (SEQ ID NO: 22), which
is amino acids 99 to 128, inclusive, of SEQ ID NO: 21; or has the sequence DALPSSEDDDDDDDSSSEEKETDNTKPNRMPV
(SEQ ID NO: 26), which is amino acids 99 to 130, inclusive, of SEQ ID NO: 25. The
D1-D2 linker of FGFR2 has the sequence DAISSGDDEDDTDGAEDFVSENSNNKR (SEQ ID NO: 28),
which is amino acids 105 to 131, inclusive, of SEQ ID NO: 27. The D1-D2 linker of
FGFR3 has the sequence DAPSSGDDEDGEDEAEDTGVDTG (SEQ ID NO: 32), which is amino acids
105 to 127, inclusive, of SEQ ID NO: 31. Certain exemplary FGFR4 ECD D1-D2 linker
chimeras include, but are not limited to, FGFR4 ECD D1-D2 linker chimeras having the
amino acid sequences of SEQ ID NOs: 35 to 38.
[0051] An
"FGFR4 2Ig ECD D1-D2 linker chimera" refers to an FGFR4 2Ig ECD selected from FGFR4 2Ig ECDs, FGFR4 2Ig ECD fragments,
and FGFR4 2Ig ECD variants, in which the linker region between immunoglobulin-like
domain I (D1) and immunoglobulin-like domain II (D2) (referred to herein interchangeably
as the "linker domain," "linker region," "D1-D2 linker," and "D1-D2 linker region")
has been replaced with the D1-D2 linker region from FGFR1, FGFR2, or FGFR3, as described
above for FGFR4 ECD D1-D2 linker chimeras.
[0052] The terms
"corresponding amino acid residue" and
"corresponding residue" are used interchangeably herein to refer to an amino acid residue or a gap
in the amino acid sequence (as indicated by "-") of a first FGFR ECD D1-D2 linker
region that lines up with an amino acid residue or a gap in the amino acid sequence
(as indicated by "-") of a second FGFR ECD D1-D2 linker region shown in a sequence
alignment. As defined herein, the corresponding amino acid residues between FGFR4
and FGFR1 are shown in
FIG. 11A. As defined herein, the corresponding amino acid residues between FGFR4 and FGFR2
are shown in
FIG. 11B. As defined herein, the corresponding amino acid residues between FGFR4 and FGFR3
are shown in
FIG. 11C. As defined herein, the corresponding amino acid residues between FGFR1 and FGFR2
are shown in
FIG. 11D. As defined herein, the corresponding amino acid residues between FGFR1 and FGFR3
are shown in
FIG. 11E. In certain embodiments, the amino acid residue of a first FGFR ECD is replaced by
the corresponding amino acid residue of a second FGFR ECD. In certain such embodiments,
when the corresponding amino acid of the second FGFR ECD is a gap, the amino acid
residue of the first FGFR ECD is deleted. In certain such embodiments, when the amino
acid residue of the first FGFR ECD is a gap, the corresponding amino acid residue
of the second FGFR ECD is inserted into the first FGFR
[0053] The terms
"corresponding amino acid sequence" and
"corresponding sequence" are used interchangeably herein to refer to the sequence of amino acid residues within
a particular region of an FGFR ECD.
[0054] An
"FGFR4 ECD exon 4 chimera" refers to an FGFR4 ECD selected from native FGFR4 ECDs, FGFR4 ECD fragments, and
FGFR4 ECD variants, in which the amino acid sequence encoded by exon 4 (referred to
herein interchangeably as "exon 4" or "exon 4 region") has been replaced with the
amino acid sequence encoded by exon 4 from FGFR1, FGFR2, or FGFR3. Exon 4 of the FGFR4
ECD encodes the sequence DSLTSSNDDEDPKSHRDPSNRHSYPQ (SEQ ID NO: 18), which is amino
acids 98 to 123, inclusive, of SEQ ID NO: 1; or encodes the sequence DSLTSSNDDEDPKSHRDLSNRHSYPQ
(SEQ ID NO: 19), which is amino acids 98 to 123, inclusive, of SEQ ID NO: 2. Exon
4 of FGFR1 encodes the sequence DALPSSEDDDDDDDSSSEEKETDNTKPN (SEQ ID NO: 23), which
is amino acids 99 to 126, inclusive, of SEQ ID NO: 21; or encodes the sequence DALPSSEDDDDDDDSSSEEKETDNTKPNRM
(SEQ ID NO: 92), which is amino acids 99 to 128, inclusive, of SEQ ID NO: 25. Exon
4 of FGFR2 encodes the sequence DAISSGDDEDDTDGAEDFVSENSNNK (SEQ ID NO: 29), which
is amino acids 105 to 130, inclusive, of SEQ ID NO: 27. Exon 4 of FGFR3 encodes the
sequence DAPSSGDDEDGEDEAEDTGVDT (SEQ ID NO: 33), which is amino acids 105 to 126,
inclusive, of SEQ ID NO: 31. Certain exemplary FGFR4 ECD exon 4 chimeras include,
but are not limited to, FGFR4 ECD exon 4 chimeras having the amino acid sequences
of SEQ ID NOs: 39 to 42.
[0055] An
"FGFR4 2Ig ECD exon 4 chimera" refers to an FGFR4 2Ig ECD selected from FGFR4 2Ig ECDs, FGFR4 2Ig ECD fragments,
and FGFR4 2Ig ECD variants, in which the amino acid sequence encoded by exon 4 (referred
to herein interchangeably as "exon 4" or "exon 4 region") has been replaced with the
amino acid sequence encoded by exon 4 from FGFR1, FGFR2, or FGFR3, as described above
for FGFR4 ECD exon 4 chimeras.
[0056] An
"FGFR4 ECD acid box chimera" refers to an FGFR4 ECD selected from native FGFR4 ECDs, FGFR4 ECD fragments, and
FGFR4 ECD variants, in which at least the acid box has been replaced with at least
the acid box from FGFR1, FGFR2, or FGFR3. As defined herein, the acid box of FGFR4
has the sequence DDEDPKSHR (SEQ ID NO: 20). As defined herein, the acid box of FGFR1
has the sequence EDDDDDDDSS SE (SEQ ID NO: 24). As defined herein, the acid box of
FGFR2 has the sequence DDEDD'TD (SEQ ID NO: 30). As defined herein, the acid box of
FGFR3 has the sequence DDEDGE (SEQ ID NO: 34).
[0057] An
"FGFR4 2Ig ECD acid box chimera" refers to an FGFR4 ECD selected from FGFR4 2Ig ECDs, FGFR4 2Ig ECD fragments, and
FGFR4 2Ig ECD variants, in which at least the acid box has been replaced with at least
the acid box from FGFR1, FGFR2, or FGFR3, as described above for FGFR4 ECD acid box
chimeras.
[0058] As used herein, the term
"acid box region" means a region of an FGFR ECD that includes the acid box defined above, along with
additional amino acids from the FGFR ECD sequence on either the amino-terminus, the
carboxy-terminus, or both the amino-terminus and the carboxy-terminus of the acid
box, up to and including all of the additional amino acids found in the D1-D2 linker
of the FGFR ECD, as defined above. As defined herein, the term FGFR4 ECD acid box
chimera includes polypeptides in which the acid box of FGFR4 is replaced with an acid
box region from FGFR1, FGFR2, or FGFR3. The term FGFR4 ECD acid box chimera also includes
polypeptides in which an acid box region of FGFR4 is replaced with an acid box region
from FGFR1, FGFR2, or FGFR3. The term FGFR4 ECD acid box chimera also includes polypeptides
in which an acid box region of FGFR4 is replaced with the acid box from FGFR1, FGFR2,
or FGFR3. Certain exemplary FGFR4 ECD acid box chimeras include, but are not limited
to, FGFR4 ECD acid box chimeras having the amino acid sequences of SEQ ID NOs: 43
to 45 and 157.
[0059] A
"long acid box" refers to a region of an FGFR ECD that includes the acid box and certain additional
amino acid residues on the amino-terminus and/or carboxy-terminus of the acid box.
As defined herein, the long acid box of the FGFR4 ECD has the sequence NDDEDPKSHRDPSNR
(SEQ ID NO: 96), which is amino acids 104 to 118, inclusive, of SEQ ID NO: 1; or has
the sequence NDDEDPKSHRDLSNR (SEQ ID NO: 97), which is amino acids 104 to 118, inclusive,
of SEQ ID NO: 2. As defined herein, the long acid box of the FGFR1 ECD has the sequence
EDDDDDDDSSSEEKETD (SEQ ID NO: 98), which is amino acids 105 to 121, inclusive, of
SEQ ID NOs: 21 and 25. As defined herein, the long acid box of the FGFR2 ECD has the
sequence DDEDDTDGAEDFVSE (SEQ ID NO: 99), which is amino acids 111 to 125, inclusive,
of SEQ ID NO: 27. As defined herein, the long acid box of the FGFR3 ECD has the sequence
GDDEDGEDEAED (SEQ ID NO: 100), which is amino acids 110 to 121, inclusive, of SEQ
ID NO: 31.
[0060] The term
"FGFR4 ECD long acid box chimera" refers to an FGFR4 ECD selected from native FGFR4 ECDs, FGFR4 ECD fragments, and
FGFR4 ECD variants, in which at least the long acid box, but not more than the D1-D2
linker region, has been replaced with at least the long acid box, but not more than
the D1-D2 linker region, from FGFR1, IFGFR2, or FGFR3.
[0061] The term
"FGFR4 2Ig ECD long acid box chimera" refers to an FGFR4 ECD selected from native FGFR4 2Ig ECDs, FGFR4 2Ig ECD fragments,
and FGFR4 2 Ig ECD variants, in which at least the long acid box, but not more than
the D1-D2 linker region, has been replaced with at least the long acid box, but not
more than the D1-D2 linker region, from FGFR1, FGFR2, or FGFR3.
[0062] The term
"short acid box" refers to a region of an FGFR ECD having a stretch of consecutive acidic amino acid
residues within the acid box. As defined herein, the short acid box of the FGFR4 ECD
has the sequence DDED (SEQ ID NO: 101), which is amino acids 105 to 108, inclusive,
of SEQ ID NOs: 1 and 2. As defined herein, the short acid box of the FGFR1 ECD has
the sequence EDDDDDDD (SEQ ID NO: 102), which is amino acids 105 to 112, inclusive,
of SEQ ID NOs: 21 and 25. As defined herein, the short acid box of the FGFR2 ECD has
the sequence DDEDD (SEQ ID NO: 103), which is amino acids 111 to 115, inclusive, of
SEQ ID NO: 27. As defined herein, the short acid box of the FGFR3 ECD has the sequence
DDED (SEQ ID NO: 104), which is amino acids 111 to 114, inclusive, of SEQ ID NO: 31.
[0063] The term
"FGFR4 ECD short acid box chimera" refers to an FGFR4 ECD selected from native FGFR4 ECDs, FGFR4 ECD fragments, and
FGFR4 ECD variants, in which at least the short acid box, but not more than the D1-D2
linker region, from FGFR4 has been replaced with at least the short acid box, but
not more than the D1-D2 linker region, from FGFR1, FGFR2, or FGFR3.
[0064] The term
"FGFR4 2Ig ECD short acid box chimera" refers to an FGFR4 ECD selected from native FGFR4 2Ig ECDs, FGFR4 2Ig ECD fragments,
and FGFR4 2Ig ECD variants, in which at least the short acid box, but not more than
the D1-D2 linker region, from FGFR4 has been replaced with at least the short acid
box, but not more than the D1-D2 linker region, from FGFR1, FGFR2, or FGFR3.
[0065] The term
"FGFR2 ECD short acid box chimera" refers to an FGFR2 ECD selected from native FGFR2 ECDs, FGFR2 ECD fragments, and
FGFR2 ECD variants in which at least the short acid box, but not more than the D1-D2
linker region, from FGFR2 has been replaced with at least the short acid box, but
not more than the D1-D2 linker region, from FGFR1. In certain embodiments of the FGFR2
ECD short acid box chimera, at least the FGFR2 acid box, but not more than the D1-D2
linker region, is replaced with the FGFR1 short acid box.
[0066] The term
"FGFR3 ECD short acid box chimera" refers to an FGFR3 ECD selected from native FGFR3 ECDs, FGFR3 ECD fragments, and
FGFR3 ECD variants in which at least the short acid box, but not more than the D1-D2
linker region, from FGFR3 has been replaced with at least the short acid box, but
not more than the D1-D2 linker region, from FGFR1. In certain embodiments of the FGFR3
ECD short acid box chimera, at least the FGFR3 acid box, but not more than the D1-D2
linker region, is replaced with the FGFR1 short acid box.
[0067] The term
"FGFR4 ECD acidic region chimera" is used herein for convenience to refer to the following five types of molecules:
FGFR4 ECD D1-D2 linker chimeras, FGFR4 ECD exon 4 chimeras, FGFR4 ECD acid box chimeras,
FGFR4 ECD long acid box chimeras, and FGFR4 ECD short acid box chimeras.
[0068] The term
"FGFR4 2Ig ECD acidic region chimera" is used herein for convenience to refer to the following five types of molecules:
FGFR4 2Ig ECD D1-D2 linker chimeras, FGFR4 2Ig ECD exon 4 chimeras, FGFR4 2Ig ECD
acid box chimeras, FGFR4 2Ig ECD long acid box chimeras, and FGFR4 2Ig ECD short acid
box chimeras.
[0069] The term
"FGFR4 ECD long acid box variant" refers to variants of the FGFR4 ECD selected from native FGFR4 ECDs, FGFR4 ECD fragments,
and FGFR4 ECD variants, that have increased acidity in the long acid box relative
to the FGFR4 wild-type long acid box. In certain embodiments of FGFR4 ECD long acid
box variants, at least two non-acidic residues within the long acid box of the FGFR4
ECD are each independently replaced with an acidic residue. In certain embodiments
of FGFR4 ECD long acid box variants, at least one residue within the long acid box
of the FGFR4 ECD is replaced with the corresponding amino acid residue from FGFR1,
FGFR2, or FGFR3. In certain embodiments of FGFR4 ECD long acid box variants, at least
one acidic residue within the long acid box of the FGFR4 ECD is replaced with a different
acidic residue. In certain embodiments of FGFR4 ECD long acid box variants, one or
two acidic residues are inserted between amino acids 103 and 104 of SEQ ID NOs: 1
and 2. In certain embodiments of FGFR4 ECD long acid box variants, up to three non-acidic
residues are deleted from the long acid box of the FGFR4 ECD. In certain embodiments
of FGFR4 ECD long acid box variants, the total number of acidic residues within the
long acid box of an FGFR4 ECD acidic region variant, including any acidic residues
inserted between amino acids 103 and 104 of SEQ ID NOs: 1 and 2, is at least seven.
[0070] The term
"FGFR4 2Ig ECD long acid box variant" refers to variants of the FGFR4 ECD selected from native FGFR4 2Ig ECDs, FGFR4 2Ig
ECD fragments, and FGFR4 2Ig ECD variants, that have increased acidity in the long
acid box relative to the FGFR4 wild-type long acid box. In certain embodiments of
FGFR4 2Ig ECD long acid box variants, at least two non-acidic residues within the
long acid box of the FGFR4 2Ig ECD are replaced with an acidic residue. In certain
embodiments of FGFR4 2Ig ECD long acid box variants, at least one residue within the
long acid box of the FGFR4 2Ig ECD is replaced with the corresponding amino acid residue
from FGFR1, FGFR2, or FGFR3. In certain embodiments of FGFR4 2Ig ECD long acid box
variants, at least one acidic residue within the long acid box of the FGFR4 2Ig ECD
is replaced with a different acidic residue. In certain embodiments of FGFR4 2Ig ECD
long acid box variants, one or two acidic residues are inserted between amino acids
15 and 16 of SEQ ID NO: 94, which is an exemplary FGFR4 2Ig ECD. In certain embodiments
of FGFR4 2Ig ECD long acid box variants, up to three non-acidic residues are deleted
from the long acid box of the FGFR4 In certain embodiments of FGFR4 2Ig ECD long acid
box variants, the total number of acidic residues within the long acid box of an FGFR4
2Ig ECD acidic region variant, including any acidic residues inserted between amino
acids 15 and 16 of SEQ ID NO: 94, is at least seven.
[0071] An
"FGFR4 ECD acidic region mutein" is an FGFR4 ECD selected from native FGF4 ECDs, FGFR4 ECD fragments, and FGFR4 ECD
variants having a greater number of acidic residues in the D1-D2 linker region than
the wild-type FGFR4 ECD. The term FGFR4 ECD acidic region mutein is used herein to
refer to the following types of molecules: FGFR4 ECD acidic region chimeras, including
FGFR4 ECD D1-D2 linker chimeras, FGFR4 ECD exon 4 chimeras, FGFR4 ECD acid box chimeras,
FGFR4 ECD long acid box chimeras, and FGFR4 ECD short acid box chimeras; and FGFR4
ECD long acid box variants.
[0072] An
"FGFR4 2Ig ECD acidic region mutein" is an FGFR4 2Ig ECD selected from native FGFR4 2Ig ECDs, FGFR4 2Ig ECD fragments,
and FGFR4 2Ig ECD variants having a greater number of acidic residues in the D1-D2
linker region than the wild-type FGFR4 2Ig ECD. The term FGFR4 2Ig ECD acidic region
mutein is used herein to refer to the following types of molecules: FGFR4 2Ig ECD
acidic region chimeras, including FGFR4 2Ig ECD D1-D2 linker chimeras, FGFR4 2Ig ECD
exon 4 chimeras, FGFR4 2Ig ECD acid box chimeras, FGFR4 2Ig ECD long acid box chimeras,
and FGFR4 2Ig ECD short acid box chimeras; and FGFR4 2Ig ECD long acid box variants.
[0073] An
"FGFR2 ECD acidic region mutein" is an FGFR2 ECD selected from native FGFR2 ECDs, FGFR2 ECD fragments, and FGFR2 ECD
variants having a greater number of acidic residues in the D1-D2 linker region than
the wild-type FGFR2
[0074] An
"FGFR3 ECD acidic region mutein" is an FGFR3 ECD selected from native FGFR3 ECDs, FGFR3 ECD fragments, and FGFR3 ECD
variants having a greater number of acidic residues in the D1-D2 linker region than
the wild-type FGFR3 ECD.
[0075] The term
"FGFR4 ECD fusion molecule" refers to a molecule comprising a polypeptide selected from an FGFR4 ECD and an FGFR4
ECD acidic region mutein, and a fusion partner. The term
"FGFR4 2Ig ECD fusion molecule" refers to a molecule comprising a polypeptide selected from an FGFR4 2Ig ECD and
an FGFR4 2Ig ECD acidic region mutein, and a fusion partner. The term
"FGFR2 ECD fusion molecule" refers to a molecule comprising a polypeptide selected from an FGFR2 ECD and an FGFR2
ECD acidic region mutein, and a fusion partner. In certain embodiments, an FGFR2 ECD
fusion molecule contains a "GS" linker between the FGFR2 ECD or the FGFR2 ECD acidic
region mutein and the fusion partner. The term
"FGFR3 ECD fusion molecule" refers to a molecule comprising a polypeptide selected from an FGFR3 ECD and an FGFR3
ECD acidic region mutein, and a fusion partner. In certain embodiments, an FGFR3 ECD
fusion molecule contains a "GS" linker between the FGFR3 ECD or the FGFR3 ECD acidic
region mutein and the fusion partner. The fusion partner may be linked to either the
amino-terminus or the carboxy-terminus of the polypeptide. In certain embodiments,
the polypeptide and the fusion partner are covalently linked. If the fusion partner
is also a polypeptide ("the fusion partner polypeptide"), the polypeptide and the
fusion partner polypeptide may be part of a continuous amino acid sequence. In such
cases, the polypeptide and the fusion partner polypeptide may be translated as a single
polypeptide from a coding sequence that encodes both the polypeptide and the fusion
partner polypeptide. In certain embodiments, the polypeptide and the fusion partner
are covalently linked through other means, such as, for example, a chemical linkage
other than a peptide bond. Many methods of covalently linking polypeptides to other
molecules (for example, fusion partners) are known in the art. One skilled in the
art can select a suitable method of covalent linkage based on the particular polypeptide
and fusion partner to be covalently linked.
[0076] In certain embodiments, the polypeptide and the fusion partner are noncovalently
linked. In certain such embodiments, they may be linked, for example, using binding
pairs. Exemplary binding pairs include, but are not limited to, biotin and avidin
or streptavidin, an antibody and its antigen, etc.
[0077] Certain exemplary fusion partners include, but are not limited to, an immunoglobulin
Fc domain, albumin, and polyethylene glycol. The amino acid sequences of certain exemplary
Fc domains are shown in SEQ ID NOs: 72 to 74.
[0078] The term
"signal peptide" refers to a sequence of amino acid residues that facilitates secretion of a polypeptide
from a mammalian cell. A signal peptide is typically cleaved upon export of the polypeptide
from the mammalian cell. Certain exemplary signal peptides include, but are not limited
to, the signal peptides of FGFR1, FGFR2, FGFR3, and FGFR4, such as, for example, the
amino acid sequences of SEQ ID NOs: 66 to 69, and 75. Certain exemplary signal peptides
also include signal peptides from heterologous proteins. A "signal sequence" refers
to a polynucleotide sequence that encodes a signal peptide.
[0079] A
"vector" refers to a polynucleotide that is used to express a polypeptide of interest in a
host cell. A vector may include one or more of the following elements: an origin of
replication, one or more regulatory sequences (such as, for example, promoters and/or
enhancers) that regulate the expression of the polypeptide of interest, and/or one
or more selectable marker genes (such as, for example, antibiotic resistance genes
and genes that can be used in colorimetric assays, e.g., β-galactosidase). One skilled
in the art can select suitable vector elements for the particular host cell and application
at hand.
[0080] A
"host cell" refers to a cell that can be or has been a recipient of a vector or isolated polynucleotide.
Host cells may be prokaryotic cells or eukaryotic cells. Exemplary eukaryotic cells
include mammalian cells, such as primate or non-primate animal cells; fungal cells;
plant cells; and insect cells. Certain exemplary mammalian cells include, but are
not limited to, 293 and CHO cells.
[0081] The term
"isolated" as used herein refers to a molecule that has been separated from at least some of
the components with which it is typically found in nature. For example, a polypeptide
is referred to as "isolated" when it is separated from at least some of the components
of the cell in which it was produced. Where a polypeptide is secreted by a cell after
expression, physically separating the supernatant containing the polypeptide from
the cell that produced it is considered to be "isolating" the polypeptide. Similarly,
a polynucleotide is referred to as "isolated" when it is not part of the larger polynucleotide
(such as, for example, genomic DNA or mitochondrial DNA, in the case of a DNA polynucleotide)
in which it is typically found in nature, or is separated from at least some of the
components of the cell in which it was produced, e.g., in the case of an RNA polynucleotide.
Thus, a DNA polynucleotide that is contained in a vector inside a host cell may be
referred to as "isolated" so long as that polynucleotide is not found in that vector
in nature.
[0082] The terms
"subject" and
"patient" are used interchangeably herein to refer to mammals, including, but not limited to,
rodents, simians, humans, felines, canines, equines, bovines, porcines, ovines, caprines,
mammalian laboratory animals, mammalian farm animals, mammalian sport animals, and
mammalian pets.
[0083] The term
"angiogenesis" refers to the development of new blood vessels, including capillary vessels. It can
take place in healthy tissue or diseased tissue, such as, for example, cancer and
macular degeneration. The term includes neovascularization, revascularization, angiopoiesis,
and vasculogenesis. New blood vessel growth typically results from stimulation of
endothelial cells by angiogenic factors which may be active in proliferative conditions,
such as in cancer or macular degeneration. An "angiogenic factor" is one that promotes
angiogenesis.
[0084] The term
"angiogenic disorder" refers to a condition in which there is inappropriate development of new blood vessels.
[0085] "Treatment," as used herein, covers any administration or application of a therapeutic for disease
in a mammal, including a human, and includes inhibiting the disease, arresting its
development, or relieving the disease, for example, by causing regression, or restoring
or repairing a lost, missing, or defective function; or stimulating an inefficient
process. Treatment may achieved with surgery, radiation, and/or administration of
one or more molecules, including, but not limited to, small molecules and polymers,
such as polypeptides.
[0086] A
"pharmaceutically acceptable carrier" refers to a non-toxic solid, semisolid, or liquid filler, diluent, encapsulating
material, formulation auxiliary, or carrier conventional in the art for use with a
therapeutic agent for administration to a subject. A pharmaceutically acceptable carrier
is non-toxic to recipients at the dosages and concentrations employed and is compatible
with other ingredients of the formulation. The pharmaceutically acceptable carrier
is appropriate for the formulation employed. For example, if the therapeutic agent
is to be administered orally, the carrier may be a gel capsule. If the therapeutic
agent is to be administered subcutaneously, the carrier ideally is not irritable to
the skin and does not cause injection site reaction.
FGFR4 Extracellular Domains
[0087] Certain exemplary FGFR4 ECDs include native FGFR4 ECDs, FGFR4 ECD fragments, and
FGFR4 ECD variants. As noted above, an FGFR4 ECD fragment may have all or a portion
of the sequence LEASEEVE (SEQ ID NO: 70) deleted from the amino terminus and/or all
or a portion of the sequence LPEEDPTWTAAAPEARYTD (SEQ ID NO: 71) deleted from the
carboxy terminus of the polypeptide. Exemplary FGFR4 ECDs include, but are not limited
to, FGFR4 ECDs having amino acid sequences selected from SEQ ID NOs: 1, 2, 3, 93,
6 to 10, and 76 to 81.
[0088] One skilled in the art can create FGFR4 ECD variants that are capable of binding
to FGF2 and/or FGF19 based on the extensive data available on the structure/function
relationship for FGFRs.
[0089] In certain embodiments, an FGFR4 ECD is isolated.
FGFR4 ECD Acidic Region Chimeras
[0090] An FGFR4 ECD acidic region chimera is an FGFR4 ECD selected from native FGF4 ECDs,
FGFR4 ECD fragments, and FGFR4 ECD variants having a greater number of acidic residues
in the D1-D2 linker region than the wild-type FGFR4 FGFR4 ECD acidic region chimeras
include FGFR4 ECD D1-D2 linker chimeras, FGFR4 ECD exon 4 chimeras, FGFR4 ECD acid
box chimeras, FGFR4 ECD long acid box chimeras, and FGFR4 ECD short acid box chimeras.
In certain embodiments, an FGFR4 ECD acidic region chimera is isolated.
[0091] Exemplary FGFR4 ECD D1-D2 linker chimeras include, but are not limited to, FGFR4
ECDs in which the D1-D2 linker of FGFR4, DSLTSSNDDEDPKSHRDPSNRHSYPQQ or DSLTSSNDDEDPKSHRDLSNRHSYPQQ
(SEQ ID NO: 16 or 17, respectively) has been replaced with the D1-D2 linker of FGFR1,
DALPSSEDDDDDDDSSSEEKETDNTKPNPV or DALPSSEDDDDDDDSSSEEKETDNTKPNRMPV (SEQ ID NO: 22
or 26, respectively (collectively referred to as "FGFR4 ECD R1 D1-D2 linker chimeras"
and "FGFR4 ECD R1 RM D1-D2 linker chimeras," respectively), the D1-D2 linker of FGFR2,
DAISSGDDTGAEDFVSENSNNKR (SEQ ID NO: 28) (collectively referred to as "FGFR4 ECD R2
D1-D2 linker chimeras"), or the D1-D2 linker of FGFR3, DAPSSGDDEDGEDEAEDTGVDTG (SEQ
ID NO: 32) (collectively referred to as "FGFR4 ECD R3 D1-D2 linker chimeras").
[0092] As discussed above for FGFR4 ECDs, FGFR4 ECD D1-D2 linker chimeras may include or
lack a signal peptide. FGFR4 ECD D1-D2 linker chimeras may have all or a portion of
the sequence LEASEEVE (SEQ ID NO: 70) deleted from the amino terminus and/or all or
a portion of the sequence LPEEDPTWTAAAPEARYTD (SEQ ID NO: 71) deleted from the carboxy
terminus of the polypeptide. Exemplary FGFR4 ECD D1-D2 linker chimeras include, but
are not limited to, the FGFR4 ECD D1-D2 linker chimeras having amino acid sequences
selected from SEQ ID NOs: 35 to 38. In certain embodiments, FGFR4 ECD D1-D2 linker
chimeras comprise at least one FGFR4 ECD glycosylation mutation. Exemplary FGFR4 ECD
D1-D2 linker chimeras comprising glycosylation mutations include, but are not limited
to, the FGFR4 ECD D1-D2 linker chimera of SEQ ID NO: 35 with the N91A glycosylation
mutation, the N159A glycosylation mutation, or both the N91A and N159A glycosylation
mutations. In certain embodiments, an FGFR4 ECD D1-D2 linker chimera glycosylation
mutants comprise an amino acid sequence selected from SEQ ID NOs: 120, 121, and 168.
[0093] Exemplary FGFR4 ECD exon 4 chimeras include, but are not limited to, FGFR4 ECDs in
which the FGFR4 exon 4 amino acid sequence, DSLTSSNDDEDPKSHRDPSNRHSYPQ or DSLTSSNDDEDPKSHRDLSNRHSYPQ
(SEQ ID NOs: 18 and 19, respectively), has been replaced with the FGFR1 exon 4 amino
acid sequence, DALPSSEDDDDDDDSSSEEKETDNTKPN (SEQ ID NO: 23) or DALPSSEDDDDDDDSSSEEKETDNTKPNRM
(SEQ ID NO: 92) (collectively referred to as "FGF4 ECD R1 exon 4 chimeras"), the FGFR2
exon 4 amino acid sequence, DAISSGDDEDDTDGAEDFVSENSNNK (SEQ ID NO: 29) (collectively
referred to as "FGFR4 ECD R2 exon 4 chimeras"), or the FGFR3 exon 4 amino acid sequence,
DAPSSGDDEDGEDEAEDTGVDT (SEQ ID NO: 33) (collectively referred to as "FGFR4 ECD R3
exon 4 chimeras").
[0094] As discussed above for FGFR4 ECDs, FGFR4 ECD exon 4 chimeras may include or lack
a signal peptide. FGFR4 ECD exon 4 chimeras may have all or a portion of the sequence
LEASEEVE (SEQ ID NO: 70) deleted from the amino terminus and/or all or a portion of
the sequence LPEEDPTWTAAAPEARYTD (SEQ ID NO: 71) deleted from the carboxy terminus
of the polypeptide. Exemplary FGFR4 ECD exon 4 chimeras include, but are not limited
to, the FGFR4 ECD exon 4 linker chimeras having amino acid sequences selected from
SEQ ID NOs: 39-42. In certain embodiments, an FGFR4 ECD exon 4 chimera comprises the
amino acid sequence of SEQ ID NO: 39. In certain embodiments, FGFR4 ECD exon 4 chimeras
comprise at least one FGFR4 ECD glycosylation mutation.
[0095] Exemplary FGFR4 ECD acid box chimeras include, but are not limited to, FGFR4 ECDs
in which at least the FGFR4 acid box, defined herein as DDEDPKSHR (SEQ ID NO: 20)
has been replaced with at least the FGFR1 acid box, defined herein as EDDDDDDDSSSE
(SEQ ID NO: 24) (collectively referred to as "FGFR4 ECD R1 acid box chimeras"), at
least the FGFR2 acid box, defined herein as DDEDDTD (SEQ ID NO: 30) (collectively
referred to as "FGFR4 ECD R2 acid box chimeras"), or at least the FGFR3 acid box,
defined herein as DDEDGE (SEQ ID NO: 34) (collectively referred to as "FGFR4 ECD R3
acid box chimeras").
[0096] In certain embodiments, additional amino acids flanking the acid box sequences noted
above are also replaced in the FGFR4 ECD and/or are also inserted from the FGFR1,
FGFR2, or FGFR3 ECD. Such acid boxes including additional amino acids are called "acid
box regions." In certain embodiments, additional amino acids from the FGFR1, FGFR2,
or FGFR3 acid box region are included up to, and including, the next acidic amino
acid. Thus, for example, an FGFR4 acid box or FGFR4 acid box region (e.g., an amino
acid sequence selected from SEQ ID NOs: 20 and 46 to 55) may be replaced with an FGFR1
acid box or FGFR1 acid box region having an amino acid sequence selected from EDDDDDDDSSSE
(SEQ ID NO: 24), EDDDDDDDSSSEE (SEQ ID NO: 56), EDDDDDDDSSSEEKE (SEQ ID NO: 57), and
EDDDDDDDSSSEEKETD (SEQ ID NO: 58). Similarly, an FGFR4 acid box or FGFR4 acid box
region may replaced with an FGFR2 acid box or FGFR2 acid box region having an amino
acid sequence selected from DDEDDTD (SEQ ID NO: 30), DDEDDTDGAE (SEQ ID NO: 59), DDEDDTDGAED
(SEQ ID NO: 60), and DDEDDTDGAEDFVSE (SEQ ID NO: 61). Finally, an FGFR4 acid box or
FGFR4 acid box region may replaced with an FGFR3 acid box or FGFR3 acid box region
having an amino acid sequence selected from DDEDGE (SEQ ID NO: 34), DDEDGED (SEQ ID
NO: 62), DDEDGEDE (SEQ ID NO: 63), DDEDGEDEAE (SEQ ID NO: 64), and DDEDGEDEAED (SEQ
ID NO: 65). In certain embodiments, additional amino acids may also be replaced, up
to and including all of the amino acids in the D1-D2 linker, for example, in order
to retain a particular spacing or structure in the acid box region.
[0097] As non-limiting examples, an FGFR4 acid box having the amino acid sequence of SEQ
ID NO: 21 or an FGFR4 acid box region having an amino acid sequence selected from
SEQ ID NOs: 46 to 55 may be replaced with (1) an FGFR1 acid box having the amino acid
sequence of SEQ ID NO: 24 or an FGFR1 acid box region having an amino acid sequence
selected from SEQ ID NOs: 56 to 58; (2) an FGFR2 acid box having the amino acid sequence
of SEQ ID NO: 30 or an FGFR2 acid box region having an amino acid sequence selected
from SEQ ID NOs: 59 to 61; or (3) an FGFR3 acid box having the amino acid sequence
of SEQ ID NO: 34 or an FGFR3 acid box region having an amino acid sequence selected
from SEQ ID NOs: 62 to 65. In certain embodiments, the FGFR4 acid box region of SEQ
ID NO: 51 is replaced with the FGFR1 acid box region of SEQ ID NO: 56.
[0098] As discussed above for FGFR4 ECDs, FGFR4 ECD acid box chimeras may include or lack
a signal peptide. FGFR4 ECD acid box chimeras may have all or a portion of the sequence
LEASEEVE (SEQ ID NO: 70) deleted from the amino terminus and/or all or a portion of
the sequence LPEEDPTWTAAAPEARYTD (SEQ ID NO: 71) deleted from the carboxy terminus
of the polypeptide. Exemplary FGFR4 ECD acid box chimeras include, but are not limited
to, FGFR4 ECD acid box chimeras having amino acid sequences selected from SEQ ID NOs:
44 to 45 and 157. In certain embodiments, FGFR4 ECD acid box chimeras comprise at
least one FGFR4 ECD glycosylation mutation.
[0099] Exemplary FGFR4 ECD long acid box chimeras include, but are not limited to, FGFR4
ECDs in which at least the long acid box of FGFR4, NDDEDPKSHRDPSNR or NDDEDPKSHRDLSNR
(SEQ ID NO: 96 or 97, respectively), but not more than the D1-D2 linker region, has
been replaced with at least the long acid box of FGFR1, EDDDDDDDSSSEEKETD (SEQ ID
NO: 98), but not more than the D1-D2 linker region (collectively referred to as "FGFR4
ECD R1 long acid box chimeras"); at least the long acid box of FGFR2, DDEDDTDGAEDFVSE
(SEQ ID NO: 99), but not more than the D1-D2 linker region (collectively referred
to as "FGFR4 ECD R2 long acid box chimeras"); or at least the long acid box of FGFR3,
GDDEDGEDEAED (SEQ ID NO: 100), but not more than the D1-D2 linker region (collectively
referred to as "FGFR4 ECD R3 long acid box chimeras").
[0100] As discussed above for FGFR4 ECDs, FGFR4 ECD long acid box chimeras may include or
lack a signal peptide. FGFR4 ECD long acid box chimeras may have all or a portion
of the sequence LEASEEVE (SEQ ID NO: 70) deleted from the amino terminus and/or all
or a portion of the sequence LPEEDPTWTAAAPEARYTD (SEQ ID NO: 71) deleted from the
carboxy terminus of the polypeptide. Exemplary FGFR4 ECD long acid box chimeras include,
but are not limited to, the FGFR4 ECD long acid box chimeras having amino acid sequences
selected from SEQ ID NOs: 105-107. In certain embodiments, FGFR4 ECD long acid box
chimeras comprise at least one FGFR4 ECD glycosylation mutation.
[0101] Exemplary FGFR4 ECD short acid box chimeras include, but are not limited to, FGFR4
ECDs in which at least the short acid box of FGFR4, DDED (SEQ ID NO: 101), but not
more than the D1-D2 linker region, has been replaced with at least the short acid
box of FGFR1, EDDDDDDD (SEQ ID NO: 102), but not more than the D1-D2 linker region
(collectively referred to as "FGFR4 ECD R1 short acid box chimeras"); at least the
short acid box of FGFR2, DDEDD (SEQ ID NO: 103), but not more than the D1-D2 linker
region (collectively referred to as "FGFR4 ECD R2 short acid box chimeras"); or at
least the short acid box of FGFR3, DDED (SEQ ID NO: 104), but not more than the D1-D2
linker region (collectively referred to as "FGFR4 ECD R3 short acid box chimeras").
[0102] As discussed above for FGFR4 ECDs, FGFR4 ECD short acid box chimeras may include
or lack a signal peptide. FGFR4 ECD short acid box chimeras may have all or a portion
of the sequence LEASEEVE (SEQ ID NO: 70) deleted from the amino terminus and/or all
or a portion of the sequence LPEEDPTWTAAAPEARYTD (SEQ ID NO: 71) deleted from the
carboxy terminus of the polypeptide. Exemplary FGFR4 ECD short acid box chimeras include,
but are not limited to, the FGFR4 ECD short acid box chimeras having amino acid sequences
selected from SEQ ID NOs: 108-110. In certain embodiments, FGFR4 ECD short acid box
chimeras comprise at least one FGFR4 ECD glycosylation mutation.
FGFR4 ECD Long Acid Box Variants
[0103] FGFR4 ECD long acid box variants include variants of the FGFR4 ECD that have an increased
number of acidic amino acid residues in the long acid box relative to the FGFR4 wild-type
long acid box. Exemplary FGFR4 ECD long acid variants include, but are not limited
to, variants of the FGFR4 ECD in which at least two non-acidic residues within the
long acid box of the FGFR4 ECD are each replaced with acidic residues; variants of
the FGFR4 ECD in which at least one residue within the long acid box of the FGFR4
ECD is replaced with the corresponding amino acid residue from FGFR1, FGFR2, or FGFR3;
variants of the FGFR4 ECD in which at least one acidic residue within the FGFR4 ECD
long acid box is replaced with another acidic residue; variants of the FGFR4 ECD in
which up to three non-acidic residues are deleted from the long acid box of the FGFR4
ECD; and variants of the FGFR4 long acid box in which the total number of acidic residues
within the FGFR4 ECD long acid box, including any acidic residues inserted between
amino acids 103 and 104 of SEQ ID NOs: 1 and 2, is at least seven.
[0104] As non-limiting examples of FGFR4 ECD long acid box variants, FGFR4 ECD residue N104
is replaced with the corresponding D107 residue of FGFR1; FGFR4 ECD residue P109 is
replaced with the corresponding D112 residue of FGFR1; FGFR4 ECD residue R113 is replaced
with the corresponding E116 residue of FGFR1; and FGFR4 ECD residue S116 is replaced
with the corresponding E119 residue of FGFR1. As non-limiting examples of FGFR4 ECD
long acid box variants, FGFR4 ECD residues 104 to 114, NDDEDPKSHRD (SEQ ID NO: 145),
are replaced with FGFR1 ECD residues 106 to 117, DDDDDDDSSSEE (SEQ ID NO: 149); FGFR4
ECD residues 104 to 114, NDDEDPKSHRD (SEQ ID NO: 145), are replaced with FGFR1 ECD
residues 107 to 117, DDDDDDSSSEE (SEQ ID NO: 150); FGFR4 ECD residues 104 to 110,
NDDEDPK (SEQ ID NO: 146), are replaced with FGFR1 ECD residues 105-113, EDDDDDDDS
(SEQ ID NO: 151); FGFR4 ECD residues 113 to 116, RDPS (SEQ ID NO: 147), are replaced
with FGFR1 ECD residues 116-119, EEKE (SEQ ID NO: 152); and FGFR4 ECD residues 109
to 113, PKSHR (SEQ ID NO: 148), are replaced with FGFR1 ECD residues 112-116, DSSSE
(SEQ ID NO: 153).
[0105] As discussed above for FGFR4 ECDs, FGFR4 ECD long acid box variants may include or
lack a signal peptide. FGFR4 ECD long acid box variants may have all or a portion
of the sequence LEASEEVE (SEQ ID NO: 70) deleted from the amino terminus and/or all
or a portion of the sequence LPEEDPTWTAAAPEARYTD (SEQ ID NO: 71) deleted from the
carboxy terminus of the polypeptide. Exemplary FGFR4 ECD long acid box muteins include,
but are not limited to, the FGFR4 ECD long acid box variants having amino acid sequences
selected from SEQ ID NOs: 111 to 119. In certain embodiments, FGFR4 ECD long acid
box variants comprise at least one FGFR4 ECD glycosylation mutation.
FGFR2 ECD Short Acid Box Chimeras
[0106] Exemplary FGFR2 ECD short acid box chimeras include, but are not limited to, FGFR2
ECDs in which at least the FGFR2 acid box is replaced with the FGFR1 short acid box.
As a non-limiting example of a short acid box chimera, FGFR2 ECD residues 111 to 118,
DDEDDTDG (SEQ ID NO: 155), are replaced with FGFR1 ECD residues 105 to 112, EDDDDDDD
(SEQ ID NO: 154).
[0107] As discussed above for FGFR4 ECDs, FGFR2 ECD short acid box chimeras may include
or lack a signal peptide. Further, FGFR2 ECD short acid box chimeras include FGFR2
ECD short acid box chimeras in which one or more amino acid residues have been deleted
from the amino-terminus and/or the carboxy-terminus of the ECD, and wherein the FGFR2
ECD short acid box chimeras are capable of binding to FGF2. Non-limiting exemplary
FGFR2 ECD short acid box chimeras include, but are not limited to, FGFR2 ECD short
acid box chimeras having amino acid sequences selected from SEQ ID NOs: 122 and 164.
FGFR3 ECD Short Acid Box Chimeras
[0108] Exemplary FGFR3 ECD short acid box chimeras include, but are not limited to, FGFR3
ECDs in which at least the FGFR3 acid box is replaced with the FGFR1 short acid box.
As a non-limiting example of a short acid box chimera, FGFR3 ECD residues 110 to 117,
GDDEDGED (SEQ ID NO: 156), are replaced with FGFR1 ECD residues 105 to 112, EDDDDDDD
(SEQ ID NO: 154)
[0109] As discussed above for FGFR4 ECDs, FGFR3 ECD short acid box chimeras may include
or lack a signal peptide. Further, FGFR3 ECD short acid box chimeras include FGFR3
ECD short acid box chimeras in which one or more amino acid residues have been deleted
from the amino-terminus and/or the carboxy-terminus of the ECD, and wherein the FGFR3
ECD short acid box chimeras are capable of binding to FGF2. Non-limiting exemplary
FGFR3 ECD short acid box chimeras include, but are not limited to, the FGFR3 ECD short
acid box chimera having the amino acid sequences selected from SEQ ID NOs: 123 and
165.
FGFR ECD Fusion Molecules
[0110] FGFR ECD fusion molecules comprising an FGFR ECD and a fusion partner are provided.
In certain embodiments, an FGFR ECD fusion molecule is isolated.
Fusion Partners and Conjugates
[0111] In certain embodiments, a fusion partner is selected that imparts favorable pharmacokinetics
and/or pharmacodynamics on the FGFR ECD fusion molecule. For example, in certain embodiments,
a fusion partner is selected that increases the half-life of the FGFR ECD fusion molecule
relative to the corresponding FGFR ECD without the fusion partner. By increasing the
half-life of the molecule, a lower dose and/or less-frequent dosing regimen may be
required in therapeutic treatment. Further, the resulting decreased fluctuation in
FGFR ECD serum levels may improve the safety and tolerability of the FGFR ECD-based
therapeutics.
[0112] Many different types of fusion partners are known in the art. One skilled in the
art can select a suitable fusion partner according to the intended use. Non-limiting
exemplary fusion partners include polymers, polypeptides, lipophilic moieties, and
succinyl groups. Exemplary polypeptide fusion partners include serum albumin and an
antibody Fc domain. Exemplary polymer fusion partners include, but are not limited
to, polyethylene glycol, including polyethylene glycols having branched and/or linear
chains.
Oligomerization Domain Fusion Partners
[0113] In various embodiments, oligomerization offers certain functional advantages to a
fusion protein, including, but not limited to, multivalency, increased binding strength,
and the combined function of different domains. Accordingly, in certain embodiments,
a fusion partner comprises an oligomerization domain, for example, a dimerization
domain. Exemplary oligomerization domains include, but are not limited to, coiled-coil
domains, including alpha-helical coiled-coil domains; collagen domains; collagen-like
domains, and certain immunoglobulin domains. Certain exemplary coiled-coil polypeptide
fusion partners include the tetranectin coiled-coil domain; the coiled-coil domain
of cartilage oligomeric matrix protein; angiopoietin coiled-coil domains; and leucine
zipper domains. Certain exemplary collagen or collagen-like oligomerization domains
include, but are not limited to, those found in collagens, mannose binding lectin,
lung surfactant proteins A and D, adiponectin, ficolin, conglutinin, macrophage scavenger
receptor, and emilin.
Antibody Fc Immunoglobulin Domain Fusion Partners
[0114] Many Fc domains that could be used as fusion partners are known in the art. One skilled
in the art can select an appropriate Fc domain fusion partner according to the intended
use. In certain embodiments, a fusion partner is an Fc immunoglobulin domain. An Fc
fusion partner may be a wild-type Fc found in a naturally occurring antibody, a variant
thereof, or a fragment thereof. Non-limiting exemplary Fc fusion partners include
Fcs comprising a hinge and the CH2 and CH3 constant domains of a human IgG, for example,
human IgG1, IgG2, IgG3, or IgG4. Certain additional Fc fusion partners include, but
are not limited to, human IgA and IgM. In certain embodiments, an Fc fusion partner
comprises a C237S mutation. In certain embodiments, an Fc fusion partner comprises
a hinge, CH2, and CH3 domains of human IgG2 with a P331S mutation, as described in
U.S. Patent No. 6,900,292. Certain exemplary Fc domain fusion partners are shown in SEQ ID NOs: 72 to 74, 170,
and 171.
[0115] Certain exemplary FGFR4 ECD fusion molecules comprising an FGFR4 ECD include, but
are not limited to, polypeptides having the amino acid sequences of SEQ ID NOs: 5
and 11 to 15. Certain exemplary FGFR4 ECD fusion molecules comprising an FGFR4 ECD
acidic region chimera include, but are not limited to, polypeptides having the amino
acid sequences of SEQ ID NOs: 86 to 88 and 158. In certain embodiments, an FGFR4 ECD
fusion molecule comprises the amino acid sequence of SEQ ID NO: 86. In certain embodiments,
an FGFR4 ECD fusion molecule consists of the amino acid sequence of SEQ ID NO: 86.
Albumin Fusion Partners and Albumin-binding Molecule Fusion Partners
[0116] In certain embodiments, a fusion partner is an albumin. Certain exemplary albumins
include, but are not limited to, human serum album (HSA) and fragments of HSA that
are capable of increasing the serum half-life and/or bioavailability of the polypeptide
to which they are fused. In certain embodiments, a fusion partner is an albumin-binding
molecule, such as, for example, a peptide that binds albumin or a molecule that conjugates
with a lipid or other molecule that binds albumin. In certain embodiments, a fusion
molecule comprising HSA is prepared as described, e.g., in
U.S. Patent No. 6,686,179.
Polymer Fusion Partners
[0117] In certain embodiments, a fusion partner is a polymer, for example, polyethylene
glycol (PEG). PEG may comprise branched and/or linear chains. In certain embodiments,
a fusion partner comprises a chemically-derivatized polypeptide having at least one
PEG moiety attached. Pegylation of a polypeptide may be carried out by any method
known in the art. One skilled in the art can select an appropriate method of pegylating
a particular polypeptide, taking into consideration the intended use of the polypeptide.
Certain exemplary PEG attachment methods include, for example,
EP 0 401 384;
Malik et al., Exp. Hematol., 20:1028-1035 (1992);
Francis, Focus on Growth Factors, 3:4-10 (1992);
EP 0 154 316;
EP 0 401 384;
WO 92/16221; and
WO 95/34326. As non-limiting examples, pegylation may be performed via an acylation reaction
or an alkylation reaction, resulting in attachment of one or more PEG moieties via
acyl or alkyl groups. In certain embodiments, PEG moieties are attached to a polypeptide
through the α- or ε-amino group of one or more amino acids, although any other points
of attachment known in the art are also contemplated.
[0118] Pegylation by acylation typically involves reacting an activated ester derivative
of a PEG moiety with a polypeptide. A non-limiting exemplary activated PEG ester is
PEG esterified to N-hydroxysuccinimide (NHS). As used herein, acylation is contemplated
to include, without limitation, the following types of linkages between a polypeptide
and PEG: amide, carbamate, and urethane. See, e.g.,
Chamow, Bioconjugate Chem., 5:133-140 (1994). Pegylation by alkylation typically involves reacting a terminal aldehyde derivative
of a PEG moiety with a polypeptide in the presence of a reducing agent. Non-limiting
exemplary reactive PEG aldehydes include PEG propionaldehyde, which is water stable,
and mono C1-C10 alkoxy or aryloxy derivatives thereof. See, e.g.,
U.S. Patent No. 5,252,714.
[0119] In certain embodiments, a pegylation reaction results in poly-pegylated polypeptides.
In certain embodiments, a pegylation reaction results in mono-, di-, and/or tri-pegylated
polypeptides. One skilled in the art can select appropriate pegylation chemistry and
reaction conditions to achieve the desired level of pegylation. Further, desired pegylated
species may be separated from a mixture containing other pegylated species and/or
unreacted starting materials using various purification techniques known in the art,
including among others, dialysis, salting-out, ultrafiltration, ion-exchange chromatography,
gel filtration chromatography, and electrophoresis.
Exemplary Attachment of Fusion Partners
[0120] The fusion partner may be attached, either covalently or non-covalently, to the amino-terminus
or the carboxy-terminus of the FGFR ECD. The attachment may also occur at a location
within the FGFR ECD other than the amino-terminus or the carboxy-terminus, for example,
through an amino acid side chain (such as, for example, the side chain of cysteine,
lysine, histidine, serine, or threonine).
[0121] In either covalent or non-covalent attachment embodiments, a linker may be included
between the fusion partner and the FGFR ECD. Such linkers may be comprised of amino
acids and/or chemical moieties. One skilled in the art can select a suitable linker
depending on the attachment method used, the intended use of the FGFR ECD fusion molecule,
and the desired spacing between the FGFR ECD and the fusion partner.
[0122] Exemplary methods of covalently attaching a fusion partner to an FGFR ECD include,
but are not limited to, translation of the fusion partner and the FGFR ECD as a single
amino acid sequence and chemical attachment of the fusion partner to the FGFR ECD.
When the fusion partner and the FGFR ECD are translated as single amino acid sequence,
additional amino acids may be included between the fusion partner and the FGFR ECD
as a linker. In certain embodiments, the linker is glycine-serine ("GS"). In certain
embodiments, the linker is selected based on the polynucleotide sequence that encodes
it, to facilitate cloning the fusion partner and/or FGFR ECD into a single expression
construct (for example, a polynucleotide containing a particular restriction site
may be placed between the polynucleotide encoding the fusion partner and the polynucleotide
encoding the FGFR ECD, wherein the polynucleotide containing the restriction site
encodes a short amino acid linker sequence).
[0123] When the fusion partner and the FGFR ECD are covalently coupled by chemical means,
linkers of various sizes can typically be included during the coupling reaction. One
skilled in the art can select a suitable method of covalently attaching a fusion partner
to an FGFR ECD depending, for example, on the identity of the fusion partner and the
particular use intended for the FGFR ECD fusion molecule. One skilled in the art can
also select a suitable linker type and length, if one is desired.
[0124] Exemplary methods of non-covalently attaching a fusion partner to an FGFR ECD include,
but are not limited to, attachment through a binding pair. Exemplary binding pairs
include, but are not limited to, biotin and avidin or streptavidin, an antibody and
its antigen, etc.. Again, one skilled in the art can select a suitable method of non-covalently
attaching a fusion partner to an FGFR ECD depending, for example, on the identity
of the fusion partner and the particular use intended for the FGFR ECD fusion molecule.
The selected non-covalent attachment method should be suitable for the conditions
under which the FGFR ECD fusion molecule will be used, taking into account, for example,
the pH, salt concentrations, and temperature.
Nucleic Acid Molecules Encoding the Polypeptides of the Invention
[0125] Nucleic acid molecules comprising polynucleotides that encode the polypeptides of
the invention are provided. Nucleic acid molecules comprising polynucleotides that
encode FGFR ECD fusion molecules in which the FGFR ECD and the fusion partner are
translated as a single polypeptide, are also provided. Such nucleic acid molecules
can be constructed by one skilled in the art using recombinant DNA techniques conventional
in the art.
[0126] In certain embodiments, a polynucleotide encoding a polypeptide of the invention
comprises a nucleotide sequence that encodes a signal peptide, which, when translated,
will be fused to the amino-terminus of the FGFR polypeptide of the invention. As discussed
above, the signal peptide may be the native signal peptide, the signal peptide of
FGFR1, FGFR2, FGFR3, or FGFR4, or may be another heterologous signal peptide. The
amino acid sequences for certain exemplary FGFR signal peptides are shown, e.g., in
SEQ ID NOs: 66 to 69 and 75. Certain exemplary signal peptides are known in the art,
and are described, e.g., in the online Signal Peptide Database maintained by the Department
of Biochemistry, National University of Singapore, http://proline.bic.nus.edu.sg/spdb/index.html
(
see also Choo et al., BMC Bioinformatics, 6: 249 (2005)); and in
PCT Publication No. WO 2006/081430.
[0127] In certain embodiments, the nucleic acid molecule comprising the polynucleotide encoding
the gene of interest is an expression vector that is suitable for expression in a
selected host cell.
Expression and Production of the Proteins of the Invention
Vectors
[0128] Vectors comprising polynucleotides that encode the polypeptides of the invention
are provided. Such vectors include, but are not limited to, DNA vectors, phage vectors,
viral vectors, retroviral vectors, etc. One skilled in the art can select a suitable
vector depending on the polypeptide to be expressed and the host cell chosen for expression.
[0130] In certain embodiments, a vector is chosen for
in vivo expression of the polypeptides of the invention in animals, including humans. In
certain such embodiments, expression of the polypeptide is under the control of a
promoter that functions in a tissue-specific manner. For example, liver-specific promoters
are described, e.g., in
PCT Publication No. WO 2006/076288.
Host Cells
[0131] The polypeptides of the invention can be expressed, in various embodiments, in prokaryotic
cells, such as bacterial cells; or eukaryotic cells, such as fungal cells, plant cells,
insect cells, and mammalian cells. Such expression may be carried out, for example,
according to procedures known in the art. Certain exemplary eukaryotic cells that
can be used to express polypeptides include, but are not limited to, Cos cells, including
Cos 7 cells; 293 cells, including 293-6E and 293-T cells; CHO cells, including CHO-S
and DG44 cells; and NS0 cells. One skilled in the art can select a suitable host cell
depending on the polypeptide to be expressed, the desired use of that polypeptide,
and the scale of the production (e.g., a small amount for laboratory use, or a larger
amount for pharmaceutical use). In certain embodiments, a particular eukaryotic host
cell is selected based on its ability to make certain desired post-translational modifications
of the polypeptide of the invention. For example, in certain embodiments, CHO cells
produce FGFR4 ECD acidic region muteins and/or FGFR4 ECD fusion molecules that have
a higher level of glycosylation and/or sialylation than the same polypeptides produced
in 293 cells.
[0132] Introduction of a nucleic acid into a desired host cell can be accomplished by any
method known in the art, including, but not limited to, calcium phosphate transfection,
DEAE-dextran mediated transfection, cationic lipid-mediated transfection, electroporation,
transduction, infection, etc. Certain exemplary methods are described, e.g., in
Sambrook et al., Molecular Cloning, A Laboratory Manual, 3rd ed. Cold Spring Harbor
Laboratory Press (2001). Nucleic acids may be transiently or stably transfected in the desired host cells,
according to methods known in the art.
[0133] In certain embodiments, a polypeptide can be produced
in vivo in an animal that has been engineered or transfected with a nucleic acid molecule
encoding the polypeptide, according to methods known in the art.
Purification of FGFR ECD Polypeptides
[0134] The polypeptides of the invention can be purified by various methods known in the
art. Such methods include, but are not limited to, the use of affinity matrices, ion
exchange chromatography, and/or hydrophobic interaction chromatography. Suitable affinity
ligands include any ligands of the FGFR ECD or of the fusion partner, or antibodies
thereto. For example, a Protein A, Protein G, Protein A/G, or an antibody affinity
column may be used to bind to an Fc fusion partner to purify a polypeptide of the
invention. Antibodies to the polypeptides of the invention may also be used to purify
the polypeptides of the invention. Hydrophobic interactive chromatography, for example,
a butyl or phenyl column, may also suitable for purifying certain polypeptides. Many
methods of purifying polypeptides are known in the art. One skilled in the art can
select a suitable method depending on the identity of the polypeptide or molecule
to be purified and on the scale of the purification (i.e., the quantity of polypeptide
or molecule produced).
Therapeutic Compositions
Routes of Administration and Carriers
[0135] In various embodiments, the polypeptides of the invention can be administered
in vivo by various routes known in the art, including, but not limited to, intravenous, intra-arterial,
subcutaneous, parenteral, intranasal, intramuscular, intracardiac, intraventricular,
intratracheal, buccal, rectal, intraperitoneal, intradermal, topical, transdermal,
and intrathecal, or otherwise by implantation or inhalation. The subject compositions
can be formulated into preparations in solid, semi-solid, liquid, or gaseous forms;
including, but not limited to, tablets, capsules, powders, granules, ointments, solutions,
suppositories, enemas, injections, inhalants, and aerosols. Nucleic acid molecules
encoding the polypeptides of the invention can be coated onto gold microparticles
and delivered intradermally by a particle bombardment device, or "gene gun," as described
in the literature (see, e.g.,
Tang et al., Nature 356:152-154 (1992)). One skilled in the art can select the appropriate formulation and route of administration
according to the intended application.
[0136] In various embodiments, compositions comprising the polypeptides of the invention
are provided in formulation with pharmaceutically acceptable carriers, a wide variety
of which are known in the art (see, e.g.,
Gennaro, Remington: The Science and Practice of Pharmacy with Facts and Comparisons:
Drugfacts Plus, 20th ed. (2003);
Ansel et al., Pharmaceutical Dosage Forms and Drug Delivery Systems, 7th ed., Lippencott
Williams and Wilkins (2004);
Kibbe et al., Handbook of Pharmaceutical Excipients, 3rd ed., Pharmaceutical Press
(2000)). Various pharmaceutically acceptable carriers, which include vehicles, adjuvants,
carriers, and diluents, are available to the public. Moreover, various pharmaceutically
acceptable auxiliary substances, such as pH adjusting and buffering agents, tonicity
adjusting agents, stabilizers, wetting agents and the like, are also available to
the public. Certain non-limiting exemplary carriers include saline, buffered saline,
dextrose, water, glycerol, ethanol, and combinations thereof. One skilled in the art
can select a suitable carrier according to the intended use.
[0137] In various embodiments, compositions comprising polypeptides of the invention can
be formulated for injection by dissolving, suspending, or emulsifying them in an aqueous
or nonaqueous solvent, such as vegetable or other oils, synthetic aliphatic acid glycerides,
esters of higher aliphatic acids, or propylene glycol; and if desired, with conventional
additives such as solubilizers, isotonic agents, suspending agents, emulsifying agents,
stabilizers and preservatives. In various embodiments, the compositions may be formulated
for inhalation, for example, using pressurized acceptable propellants such as dichlorodifluoromethane,
propane, nitrogen, and the like. The compositions may also be formulated, in various
embodiments, into sustained release microcapsules, such as with biodegradable or non-biodegradable
polymers. A non-limiting exemplary biodegradable formulation includes poly lactic
acid-glycolic acid polymer. A non-limiting exemplary non-biodegradable formulation
includes a polyglycerin fatty acid ester. Certain methods of making such formulations
are described, for example, in
EP 1 125 584 A1. One skilled in the art can select a suitable formulation depending on the intended
route of administration, using techniques and components known in the art.
[0138] Pharmaceutical packs and kits comprising one or more containers, each containing
one or more doses of the polypeptides of the invention are also provided. In certain
embodiments, a unit dosage is provided wherein the unit dosage contains a predetermined
amount of a composition comprising a polypeptide of the invention, with or without
one or more additional agents. In certain embodiments, such a unit dosage is supplied
in single-use prefilled syringe for injection. In various embodiments, the composition
contained in the unit dosage may comprise saline, sucrose, or the like; a buffer,
such as phosphate, or the like; and/or be formulated within a stable and effective
pH range. Alternatively, in certain embodiments, the composition may be provided as
a lyophilized powder that can be reconstituted upon addition of an appropriate liquid,
for example, sterile water. In certain embodiments, the composition comprises one
or more substances that inhibit protein aggregation, including, but not limited to,
sucrose and arginine. In certain embodiments, a composition of the invention comprises
heparin and/or a proteoglycan.
[0139] Pharmaceutical compositions are administered in an amount effective for treatment
and/or prophylaxis of the specific indication. The effective amount is typically dependent
on the weight of the subject being treated, his or her physical or health condition,
the extensiveness of the condition to be treated, and/or the age of the subject being
treated. In general, the polypeptides of the invention are to be administered in an
amount in the range of about 50 ug/kg body weight to about 30 mg/kg body weight per
dose. Optionally, the polypeptides of the invention can be administered in an amount
in the range of about 100 ug/kg body weight to about 20 mg/kg body weight per dose.
Further optionally, the polypeptides of the invention can be administered in an amount
in the range of about 0.5 mg/kg body weight to about 20 mg/kg body weight per dose.
[0140] The compositions comprising the polypeptides of the invention can be administered
as needed to subjects. Determination of the frequency of administration can be made
by persons skilled in the art, such as an attending physician based on considerations
of the condition being treated, age of the subject being treated, severity of the
condition being treated, general state of health of the subject being treated and
the like. In certain embodiments, an effective dose of the polypeptide of the invention
is administered to a subject one or more times. In various embodiments, an effective
dose of the polypeptide of the invention is administered to the subject at least twice
a month, once a week, twice a week, or three times a week. In various embodiments,
an effective dose of the polypeptide of the invention is administered to the subject
for at least a week, at least a month, at least three months, at least six months,
or at least a year.
Combination Therapy
[0141] Polypeptides of the invention may be administered alone or with other modes of treatment.
They may be provided before, substantially contemporaneous with, or after other modes
of treatment, for example, surgery, chemotherapy, radiation therapy, or the administration
of a biologic, such as a therapeutic antibody.
Methods of Treating Diseases Using FGFR ECD Polypeptides
[0142] Results from the experiments described herein show that FGFR4 ECD acidic region muteins
retain FGFR4's ability to bind FGF2 and/or FGF19. See,
e.g.,
Example 8, including
Tables 3 and 4. Thus, those chimeras can be used in a variety of treatment methods in a similar manner
to native FGFR4 ECD
(see, e.g., U.S. Publication No.
US 2008/0171689).
[0143] For example, polypeptides of the invention may be used as ligand traps
in vivo to treat diseases associated with one or more ligands of the FGFR family, such as
FGF2 and/or FGF19. The FGFR ECD polypeptide ligand traps may be used, for example,
to treat a range of cancers and/or angiogenic disorders. In certain embodiments, the
FGFR ECD polypeptide ligand traps comprise a fusion partner such as an Fc, albumin,
or polyethylene glycol (discussed above).
[0144] In certain embodiments, FGFR4 ECD acidic region muteins may be used to treat colon
cancer. Expression of both FGFR4 and FGF19 has been detected in primary colon tumors
and several colon tumor cell lines (see,
e.g.,
Desnoyers, Oncogene, 27:85-97 (2008);
U.S. Patent Application No. 20070248604). Administration of a monoclonal antibody to FGF19 significantly reduced tumor growth
in two human colon cancer cell line xenograft models (HCT116 and Colo201;
see Desnoyers). Experiments herein demonstrate that the FGFR4 ECD acidic region chimera
ABMut1 reduced tumor growth in an HCT116 xenograft model. Reduced tumor growth was
also seen in a Colo201 model following administration of ABMut1 (data not shown).
Thus, in certain embodiments, the FGFR4 ECD acidic region muteins of the invention
may be administered, e.g., as described above, to patients who have colon cancer.
In certain embodiments, the FGFR4 ECD acidic region muteins may be administered to
colon cancer patients along with at least one other therapeutic regimen and/or agent.
[0145] FGFR4 and FGF19 expression have also been detected in liver and lung tumors (see,
e.g.,
Desnoyers, Oncogene, 27:85-97 (2008);
U.S. Patent Publication No. 2007/0248604). A monoclonal antibody against FGF19 reduced tumor burden in an FGF19-transgenic
mouse hepatocellular carcinoma model (
see Desnoyers). FGFR4 expression has also been implicated in breast cancer (see,
e.g., U.S. Patent No. 7,297,774). High FGFR4 mRNA levels in estrogen receptor-positive breast carcinomas correlated
with poor clinical benefit in patients on tamoxifen as a first-line treatment (
Meijer et al., Endocr. Relat. Cancer., 15(1):101-11 (2008)). Thus, FGFR4 ECD acidic region muteins may also be used to treat liver cancers,
breast cancers, including infiltrating ductal carcinoma and adenocarcinoma, and lung
carcinomas, including small cell lung carcinomas and non-small cell lung carcinomas.
[0146] FGFR1 and FGFR4 overexpression have also been detected in prostate cancer, with a
greater frequency of high levels of protein expression in grade 5 cancers than in
grades 1-3 (
Sahadevan et al., J. Pathol., 213(1):82-90 (2007)). Suppression of FGFR4 by RNA interference blocked prostate cancer cell proliferation
in vitro (see
id.). FGFR4 ECD acidic region muteins may therefore also be used to treat prostate cancers.
[0147] FGFR ligands, such as FGF2, are known stimulators of angiogenesis. Thus, FGFR ECD
polypeptides may be administered to patients with angiogenic disorders such as cancer
and/or macular degeneration in order to inhibit angiogenesis. Additional cancers that
may be treated with the FGFR ECD polypeptides of the invention include, for example,
sarcomas and carcinomas including, but not limited to fibrosarcomas, myxosarcomas,
liposarcomas, chondrosarcomas, osteogenic sarcomas, chordomas, angiosarcomas, endotheliosarcomas,
lymphangiosarcomas, lymphangioendotheliosarcomas, synoviomas, mesotheliomas, Ewing's
tumors, leiomyosarcomas, rhabdomyosarcomas, gastic cancers, pancreatic cancers, ovarian
cancers, prostate cancers, squamous cell carcinomas, basal cell carcinomas, adenocarcinomas,
sweat gland carcinomas, sebaceous gland carcinomas, papillary carcinomas, papillary
adenocarcinomas, cystadenocarcinomas, medullary carcinomas, bronchogenic carcinomas,
renal cell carcinomas, hepatomas, liver metastases, bile duct carcinomas, choriocarcinomas,
seminomas, embryonal carcinomas, thyroid carcinomas such as anaplastic thyroid cancers,
Wilms' tumors, cervical cancers, testicular tumors, bladder carcinomas, epithelial
carcinomas, gliomas, astrocytomas, medulloblastomas, craniopharyngiomas, ependymomas,
pinealomas, hemangioblastomas, acoustic neuromas, oligodendrogliomas, meningiomas,
melanomas, neuroblastomas, glioblastomas, and retinoblastomas. Also among the cancers
within the scope of the invention are hematologic malignancies; prostate cancer; bladder
cancer; pancreatic cancer; ovarian cancer, salivary cancer; pituitary cancer; renal
cell carcinoma; melanoma; glioblastoma; and retinoblastoma.
[0148] Tumors comprising dysproliferative changes, such as hyperplasias, metaplasias, and
dysplasias, may be treated, modulated, or prevented with FGFR ECD polypeptides as
well, such as those found in epithelial tissues, including the cervix, esophagus,
and lung, for example. Hyperplasia is a form of controlled cell proliferation involving
an increase in cell number in a tissue or organ, without significant alteration in
structure or function. By way of example, endometrial hyperplasia often precedes endometrial
cancer. Metaplasia is a form of controlled cell growth in which one type of adult
or fully differentiated cell substitutes for another type of adult cell. Metaplasia
can occur in epithelial or connective tissue cells. Atypical metaplasia involves a
somewhat disorderly metaplastic epithelium. Dysplasia is frequently a forerunner of
cancer, and is found mainly in the epithelia; it is a disorderly form of non-neoplastic
cell growth, involving losses in individual cell uniformity and in the cell's architectural
orientation. Dysplasia characteristically occurs where there exists chronic irritation
or inflammation and is often found in the cervix, respiratory passages, oral cavity,
and gall bladder. Other examples of benign tumors which can be treated, modulated,
or prevented in accordance with the present invention include arteriovenous (AV) malformations,
particularly in intracranial sites and myoleomas.
[0149] Since FGFs contribute to normal bone formation and are expressed locally in the bone
stromal environment, they may play a role in seeding, growth, and survival of bone
metastases. FGFs have been implicated in bone formation, affecting osteoprogenitor
cell replication, osteoblast differentiation, and apoptosis. Thus, agents that block
FGF/FGFR interactions, including FGFR ECD polypeptides, can be used to treat bone
metastases in cancers such as prostate cancer and breast cancer. Such agents will
not only inhibit local osteoblastic conversion events, but also inhibit initial seeding,
growth, and survival of the cancer bone metastases.
EXAMPLES
[0150] The examples discussed below are intended to be purely exemplary of the invention
and should not be considered to limit the invention in any way. The examples are not
intended to represent that the experiments below are all or the only experiments performed.
Efforts have been made to ensure accuracy with respect to numbers used (for example,
amounts, temperature, etc.) but some experimental errors and deviations should be
accounted for. Unless indicated otherwise, parts are parts by weight, molecular weight
is weight average molecular weight, temperature is in degrees Centigrade, and pressure
is at or near atmospheric.
Example 1: Construction of Certain FGFR4 ECD-Fc Fusion Molecules.
[0151] The cloning, expression and purification of the R1Mut4 fusion protein used in these
examples has been previously described (
WO 2007/014123). The cloning of the parental FGFR4 ECD-Fc fusion protein used in these examples
has also been described (
WO 2007/014123, called "R4Mut4"). For transient expression in 293-6E cells, R4Mut4 was cloned into
and expressed from vector pTT5 (Biotechnology Research Institute, Montreal, Canada).
Chimeras of the R4Mut4 fusion protein were constructed using PCR and conventional
mutagenesis techniques. The R4Mut4 chimeras were originally cloned into the mammalian
expression vector pcDNA3.1 (Invitrogen) for transient expression in 293-6E cells.
[0152] The primary sequence and domain structure of the FGFR4 moiety in the parental R4Mut4
construct is shown in
FIG. 1. The stretch of amino acids between the first and second immunoglobulin (Ig) domains
(amino acids 98 to 124) is denoted interchangeably herein as the "linker domain" "linker
region," "D1-D2 linker," and "D1-D2 linker region" (see
FIG. 1). Within the linker domain is a smaller region called the "acid box" ("AB") found
within the FGFR family. Three chimeras of the parental R4Mut4 were constructed, in
which regions within the R4Mut4 linker domain were replaced with the corresponding
sequences from the FGFR1 linker domain.
FIG. 2 shows a sequence alignment of the linker domains from FGFR1 and FGFR4 and the boundaries
and sequence of the swapped regions in the three variants, called ABMut1, ABMut2,
and ABMut3 (see
Table 1), that were constructed.
Table 1 lists the various FGFR-Fc fusion proteins used in these examples with names and brief
descriptions.
Table 1. FGFR-Fc Fusion Proteins
| Protein Name |
SEQ ID # |
Brief Description |
Short name |
| FGFR4ECD(delta17)-Fc |
14 |
Parental FGFR4ECD-Fc, which has a 17 amino acid carboxy-terminal deletion from the
FGFR4 ECD. |
R4Mut4 |
| FGFR4ECD(ABMut1: delta17)-Fc |
86 |
The D1-D2 linker from FGFR1 is swapped into R4Mut4. |
ABMut1 |
| FGFR4ECD(ABMut2: delta17)-Fc |
87 |
Exon 4 from FGFR1 is swapped into R4Mut4. |
ABMut2 |
| FGFR4ECD(ABMut3: delta17)-Fc |
158 |
An acid box region from FGFR1 is swapped into R4Mut4. |
ABMut3 |
| FGFR4ECD(2Ig+Linker)-GS linker-Fc |
89 |
The first Ig domain of R4Mut4 is deleted, but the D1-D2 linker is retained with a
GS linker. |
R4(2Ig+L) |
| FGFR4ECD(2Ig-Linker)-GS linker-Fc |
90 |
Both the first Ig domain and the D1-D2 linker are deleted from R4Mut4 with a GS linker. |
R4(2Ig-L) |
| FGFR1ECD(delta14)-Fc |
91 |
FGFR1 ECD-Fc fusion protein with 14 amino acid C-terminal deletion. |
R1Mut4 |
| FGFR1ECD-Fc |
N/A |
Commercially-available FGFR1 ECD-Fc fusion protein |
RIFc |
| FGFR2ECD-Fc |
N/A |
Commercially-available FGFR2 ECD-Fc fusion protein |
R2Fc |
| FGFR3ECD-Fc |
N/A |
Commercially-available FGFR3 ECD-Fc fusion protein |
R3Fc |
| FGFR4ECD-Fc |
N/A |
Commercially-available FGFR4 ECD-Fc fusion protein |
R4Fc |
| FGFR4ECD(R4Mut4(N104D): delta17)-Fc |
130 |
R4Mut4 with N104D point mutation. |
R4Mut4(N104D) |
| FGFR4ECD(R4Mut4(P109D): delta17)-Fc |
131 |
R4Mut4 with P109D point mutation. |
R4Mut4(P109D) |
| FGFR4ECD(R4Mut4(R113E): delta17)-Fc |
132 |
R4Mut4 with R113E point mutation. |
R4Mut4(R113E) |
| FGFR4ECD(R4Mut4(S116E): delta17)-Fc |
133 |
R4Mut4 with S116E point mutation. |
R4Mut4(S116E) |
| FGFR4ECD(R4Mut4(104-114):FGFR1(106-117): delta 17)-Fc |
134 |
Residues 106 to 117 from FGFR1 swapped into R4Mut4. |
R4(104-114):R1(106-117) |
| FGFR4ECD(R4Mut4(104-114):FGFR1(107-117): delta 17)-Fc |
135 |
Residues 107 to 117 from FGFR1 swapped into R4Mut4. |
R4(104-114):R1(107-117) |
| FGFR4ECD(R4Mut4(104-110):FGFR1(105-113): delta 17)-Fc |
136 |
Residues 105 to 113 from FGFR1 swapped into R4Mut4. |
R4(104-110):R1(105-113) |
| FGFR4ECD(R4Mut4(113-116):FGFR1(116-119): delta 17)-Fc |
137 |
Residues 116 to 119 from FGFR1 swapped into R4Mut4. |
R4(113-116):R1(116-119) |
| FGFR4ECD(R4Mut4(109-113):FGFR1(112-116): delta 17)-Fc |
138 |
Residues 112 to 116 from FGFR1 swapped into R4Mut4. |
R4(109-113):R1(112-116) |
| FGFR4ECD(ABMut1(N91A): delta 17)-Fc |
139 |
ABMut1 with N91A point mutation. |
ABMut1(N91A) |
| FGFR4ECD(ABMut1(N159A): delta 17)-Fc |
140 |
ABMut1 with N159A point mutation. |
ABMut1(N159A) |
| FGFR4ECD(R4Mut4(D1-D2):FGFR2(D1-D2): delta 17)-Fc |
143 |
D1-D2 linker from FGFR2 swapped into R4Mut4. |
R4(D1-D2):R2(D1-D2) |
| FGFR4BCD(R4Mut4(D1-D2):FGFF3(D1-D2): delta 17)-Fc |
144 |
D1-D2 linker from FGFR3 swapped into R4Mut4. |
R4(D1-D2):R3(D1-D2) |
| FGFR2ECD(delta3)-GS linker-Fc |
162 |
Parental FGFR2ECD-Fc, which has a 3 amino acid carboxy-terminal deletion from the
FGFR2 ECD and a GS linker. |
FGFR2-Fc |
| FGFR3ECD(delta3)-GS linker-Fc |
163 |
Parental FGFR3ECD-Fc, which has a 3 amino acid carboxy-terminal deletion from the
FGFR3 ECD and a GS linker. |
FGFR3-Fc |
| FGFR2ECD(FGFR2(111-118):FGFR1(105-112): delta3)-GS linker-Fc |
166 |
Residues 105-112 from FGFR1 swapped into FGFR2-Fc. |
R2(111-118):R1(105-112) |
| FGFR3ECD(FGFR3(110-117):FGFR1(105-112): delta3)-GS linker-Fc |
167 |
Residues 105-112 from FGFR1 swapped into FGFR3-Fc. |
R3(110-117):R1(105-112) |
[0153] CHO-S host cells can give higher yields and/or different glycosylation patterns for
recombinant proteins when compared to 293-6E host cells. For expression of the fusion
proteins in CHO-S host cells, we used the pTT5 and pDEF38 (ICOS Corporation, Bothell,
WA) vectors. R4Mut4 and the FGFR4 ECD-Fc acidic region muteins were subcloned into
the pTT5 and pDEF38 vectors using PCR and conventional subcloning techniques.
[0154] DG44 (Invitrogen, Carlsbad, CA) is a derivative cell line of the CHO-S cell line
that we have found can give higher yields of recombinant proteins. For expression
of the fusion proteins in DG44 host cells, we used the vector pDEF38.
Example 2: Transient Expression of Fusion Proteins in 293-6E and CHO-S Host Cells.
[0155] In certain Examples herein, fusion protein was transiently expressed in 293-6E cells.
The R4Mut4/pTT5 expression vector described in Example 1 was designed to provide transient
expression in 293-6E host cells. The 293-6E host cells used for expression were previously
adapted to serum-free suspension culture in Free-Style medium (Invitrogen). The cells
were transfected with the expression vector while in logarithmic growth phase (log
phase growth) at a cell density of between 9 x 10
5/ml and 1.2 x 10
6/ml.
[0156] In order to transfect 500 ml of 293-6E cell suspension, a transfection mixture was
made by mixing 500 micrograms (ug) of the expression vector DNA in 25 ml of sterile
phosphate buffered saline (PBS) with 1 mg of polyethylenimine (from a 1 mg/ml solution
in sterile water) in 25 ml of sterile PBS. This transfection mixture was incubated
for 15 min at room temperature. Following incubation, the transfection mixture was
added to the 293-6E cells in log phase growth for transfection. The cells and the
transfection mixture were then incubated at 37°C in 5% CO
2 for 24 hours. Following incubation, Trypton-N1 (Organotechnie S.A., La Courneuve,
France; 20% solution in sterile FreeStyle medium) was added to a final concentration
of 0.5% (v/v). The mixture was maintained at 37°C and 5% CO
2 for about 6 - 8 days until the cells reached a density of about 3 - 4 x 10
6 cells/ml and showed a viability of >80%. To harvest the fusion protein from the cell
culture medium, cells were pelleted at 400 x g for 15 min at 4°C and the supernatant
was decanted. The supernatant was cleared of cell debris by centrifugation at 3,315
x g for 15 min at 4°C. The cleared supernatant containing the fusion protein was then
submitted for purification.
[0157] To provide small batches (1- 2 mg) of R4Mut4 for
in vivo study in a short period of time, transient production from suspension CHO-S host
cells was carried out using the plasmid construct R4Mut4/pDEF38. Briefly, suspension
CHO-S cells (Invitrogen) were cultured in Freestyle CHO expression medium supplemented
with L-Glutamine (Invitrogen). The day before transfection, the CHO-S cells were seeded
into a shaker flask at a density of about 5x10
5/ml, which then reached a density of about 1x10
6/ml on the day of transfection. In order to transfect 125 ml of cell suspension, 156.25
ug of the expression vector DNA was mixed with 2.5 ml of OptiPro serum free medium.
156.25 ul of FreestyleMax transfection reagent (Invitrogen) was separately mixed with
2.5 ml of OptiPro serum free medium. The transfection mixture was made by combining
the DNA/OptiPro medium mixture and the FreestyleMax/Optipro medium mixture for 10
min at room temperature. Following incubation, the transfection mixture was added
to the CHO-S cells. The cells and the transfection mixture were then incubated at
37°C in 5% CO
2 for 6 days. Following incubation, the cell density was about 3.3-3.7 x10
6/ml with a viability of about 82-88%. The supernatant from the culture was separated
from the cells by centrifugation and collected for purification. Using this method,
1 mg of R4Mut4 can be produced from 400 ml of transiently transfected cell culture
in about 1 week.
[0158] When indicated below, the R4Mut4 variants ABMut1, ABMut2, and ABMut3 were similarly
produced by transient expression in CHO-S cells using the pDEF38 expression vectors
described in Example 1.
Example 3: Purification of Expressed Proteins.
[0159] FGFR ECD-Fc fusion proteins expressed from recombinant host cells were purified from
the cell culture supernatant using a first purification step of Protein-A affinity
chromatography, followed by a second purification step of butyl hydrophobic interaction
chromatography. For the Protein-A affinity chromatography step, the components of
the media were separated on a Mabselect Protein-A Sepharose column (GE Healthcare
Bio-Sciences, Piscataway, NJ), which will bind to the Fc region of the fusion molecule.
The column was equilibrated with ten column volumes of a sterile buffer of 10 mM Tris,
100 mM NaCl, pH 8.0; then the cell culture supernatant was applied to the column.
The column was washed with eight column volumes of sterile 10 mM Tris, 100 mM NaCl
buffer, pH 8.0. The bound material, including R4Mut4, was then eluted at a rate of
10 ml/min with a one step elution using seven column volumes of elution buffer (100
mM glycine, 100 mM NaCl, pH 2.7). Ten ml fractions were collected in tubes containing
one ml 1 M Tris pH 8.0 (Ambion, Austin, TX) to neutralize the eluate. Fractions comprising
R4Mut4 were identified by gel electrophoresis and pooled.
[0160] For the second purification step of butyl hydrophobic interaction chromatography,
pooled Protein-A column eluates were further purification on a butyl Sepharose column
using a GE Healthcare Akta Purifier 100 (GE Healthcare Bio-Sciences, Piscataway, NJ).
The column was first equilibrated with five column volumes of sterile 10 mM Tris,
1 M ammonium sulfate, pH 8.0. A half volume of 3 M ammonium sulfate was then added
to the eluate, which was then applied to the equilibrated butyl Sepharose column.
The column was washed with four column volumes of the equilibration buffer and the
bound material was eluted at a rate of five ml/min with a linear gradient starting
at 50% equilibration buffer / 50% elution buffer (10 mM Tris pH 8.0) and ending at
90% elution buffer / 10% equilibration buffer over a total volume of 20 column volumes.
Finally, an additional two column volumes of 100% elution buffer was used. Fourteen
ml fractions were collected. R4Mut4 was eluted with approximately 40-60% elution buffer.
The fractions containing the bulk of the R4Mut4 were identified by gel electrophoresis
and pooled.
[0161] After purification, endotoxin levels were checked by the limulus amoebocyte lysate
(LAL) assay (Cambrex, Walkersville, MD). Endotoxin levels were confirmed to be less
than or equal to 1 endotoxin unit (EU) per mg of R4Mut4.
Example 4: Stable Production in DG44 Cells.
[0162] The expression vector R4Mut4/pDEF38, described in Example 1, was used to transfect
DG44 host cells for stable production of R4Mut4. The untransfected DHFR-negative CHO
cell line, DG44, was cultured in CHO-CD serum free medium (Irvine Scientific, Irvine,
CA) supplemented with 8 mM L-Glutamine, 1x Hypoxanthine/Thymidine (HT; Invitrogen),
and 18 ml/L of Pluronic-68 (Invitrogen). About 50 ug of R4Mut4/pDEF38 plasmid DNA
was linearized by digestion with restriction enzyme PvuI, then precipitated by addition
of ethanol, briefly air-dried, and then resuspended in 400 ul of sterile, distilled
water. The DG44 cells were seeded into a shaker flask at a density of about 4x10
5/ml the day before transfection, and reached a density of about 0.8x10
6/ml on the day of transfection. The cells were harvested by centrifugation and about
1x10
7 cells were used per transfection.
[0163] For transfection, each cell pellet was resuspended in 0.1 ml of Nucleofector V solution
and transferred to an Amaxa Nucleofector cuvette (Amaxa, Cologne, Germany). About
5 ug of the resuspended linearized plasmid DNA was added and mixed with the suspended
DG44 cells in the cuvette. Cells were then electroporated with an Amaxa Nucleofector
Device II using program U-024. Electroporated cells were cultured in CHO-CD medium
for two days and then transferred into selective medium (CHO-CD serum free medium
supplemented with 8 mM L-Glutamine and 18 ml/L Pluronic-68). The selective medium
was changed once every week. After about 12 days, 1 ug/ml R3 Long IGF I growth factor
(Sigma, St. Louis, MO) was added to the medium and the culture was continued for another
week until confluent. The supernatants from pools of stably transfected cell lines
were assayed by a sandwich R4Mut4 ELISA to determine the product titer. This transfection
method generated an expression level of about 30 ug/ml of R4Mut4 from the pools of
stably transfected cells.
Example 5. Binding to Hepatocytes In Vitro.
[0164] Preliminary experiments demonstrated that R4Mut4 had antitumor properties in a xenograft
model yet exhibited a very fast initial serum concentration decline when injected
into the tail vein of the mouse. (Data not shown.) Follow-up experiments demonstrated
that, unlike the FGFR1 ECD fusion protein R1Mut4, R4Mut4 bound in a concentration-dependent
manner to the extracellular matrix Matrigel
in vitro. See, e.g., FIG. 6 and
Example 9. To ascertain whether the R4Mut4 was binding to liver
in vivo, further
in vitro binding experiments were conducted to determine whether R4Mut4 and R1Mut4 bound to
hepatocytes and also to determine the heparin-sensitivity of that binding.
[0165] R4Mut4 and R1Mut4 were expressed and purified from CHO-S cells as described in
Examples 2 and 3. For this experiment, three different batches of R4Mut4 were tested; each had been
expressed and purified independently. Human IgG1 control protein was obtained from
Caltag (now part of Invitrogen).
[0166] Hepatocytes were isolated from adult rats. Rats were anesthetized with isoflurane
and the animals were kept as close to 37°C as possible with a heating element. A midline
incision was made and the organs were removed from the cavity to access the portal
vein. The portal vein was cannulated with a butterfly catheter secured with a bulldog
clamp. The pump was started at 8 ml/min with Hanks Balanced Salt Solution without
Ca
2+ or Mag
2+, with 10 mM Hepes, 0.5 mM EGTA, 50 ug/ml gentamicin, pH 7.38. The inferior vena cava
(IVC) was then cut about 2 cm below the liver and an exit point was created by cutting
the heart. The flow was adjusted to 40 ml/min and once clear signs of perfusion were
observed, the IVC was clamped between the liver and the posterior cut of the IVC.
After 4 minutes, Liver Digest Media (Invitrogen) was added to the perfusion line.
Both solutions were perfused together for 30 seconds, and then the Hanks Balanced
Salt Solution was stopped. The flow rate of the Liver Digest Media was then decreased
to 20 ml/min and the perfusion continued for approximately 10 minutes. The liver was
excised and small slits in the capsule of each lobe were made. The liver was placed
on sterile gauze affixed to the top of a beaker and gently rolled around while continuously
rinsing the hepatocytes into the beaker using Liver Digest Media.
[0167] The media containing the hepatocytes was poured into 50 ml conical tubes and centrifuged
for approximately 2 minutes at 400 rpm. The media was aspirated off and 25 ml of Culture
Media (Williams Medium E (Sigma), 100 IU/ml of penicillin (Cellgro), 100 ug/ml of
streptomycin (Cellgro), 1X ITS (Insulin, Transferrin and Sodium Selenite, from Sigma)
and 10% FBS (Cellgro)) was added to half of the tubes and the cells were resuspended.
The resuspended cells were then decanted into the remaining tubes and the volume of
Culture Media was brought to 50 ml in each tube. The tubes were centrifuged again
as above and the decanting step was repeated. The cells were then resuspended in ice-cold
staining buffer (Ca
2+ and Mg
2+ free PBS (Invitrogen) supplemented with 1% bovine serum albumin (BSA; w/v) and 0.1%
NaN
3 (w/v), both from Sigma) at a concentration of 500,000 cells per ml. The hepatocytes
were then incubated with 5 ug/ml of R1Mut4, R4Mut4, or control human IgG1 for 30 minutes.
In samples where heparin was present, the R1Mut4, R4Mut4, or control human IgG1 was
pre-incubated with a 10-fold molar excess of sodium heparin (from porcine intestinal
mucosa, Catalog # 086K2231, Sigma) before mixing with the hepatocytes.
[0168] Following incubation with the fusion proteins or control IgG1, with or without heparin,
the cells were washed in staining buffer and incubated with 5 ug/ml biotinylated goat
anti- human Fc (Becton Dickinson) on ice for 30 min. The cells were then washed in
staining buffer and incubated with 1 ug/ml streptavidin-APC conjugate (Becton Dickinson)
on ice for 30 min. The cells were again washed with staining buffer and then stained
with 0.5 ug/ml propidium iodide (Sigma). Non-viable cells that had absorbed the propidium
iodide were gated out such that only viable cells were included in the flow cytometry
analysis. The viable cells were quantitated for APC fluorescence. As shown in FIG.
3, R4Mut4 showed 10-fold more binding to rat hepatocytes than either control IgG1
or R1Mut4 in that experiment. In addition, all three batches of R4Mut4 bound the rat
hepatocytes with similar affinity, indicating that the high affinity of R4Mut4 for
rat hepatocytes was not due to unusual expression or purification conditions. Finally,
the addition of heparin prevented R4Mut4 binding to hepatocytes in that experiment.
Example 6. Heparin Increases the Cmax of R4Mut4 in Plasma In Vivo.
[0169] The experiment discussed in Example 5 demonstrated that R4Mut4 bound to hepatocytes
and that heparin could interfere with that binding. To test whether heparin could
increase in the amount of R4Mut4 present in the serum
in vivo, R4Mut4 was administered to mice with and without exogenous heparin, and the amount
of R4Mut4 in the serum was analyzed by ELISA at different time points following injection.
The R4Mut4 injected in the experiment was expressed and purified from CHO-S cells
as described in Examples 2 and 3.
[0170] Thirty male Balb/C mice (Jackson Laboratories, Bar Harbor, ME) were weighed and sorted
into two groups of 15 mice each based on a random distribution of body weight. Mice
in the first group were given an intravenous injection (via tail vein) of 3 mg/kg
R4Mut4 in a total volume of 0.5 ml PBS (Cellgro, Herndon, VA). Mice in the second
group were given an intravenous injection (via tail vein) of 3 mg/kg R4Mut4 that had
been premixed with 5 mg/kg sodium heparin (from porcine intestinal mucosa, Sigma)
for 30 minutes-2 hours before IV dosing.
[0171] Blood from the mice was collected at 6 different time points after IV administration,
at approximately 2 minutes, 2 hours, 8 hours, 1 day, 4 days, and 6 days. Blood was
collected from each mouse only twice, the first by a retro-orbital bleed and the second
terminally by cardiac puncture. The 15 mice from each IV group were further divided
into three subgroups of 5 mice. The first subgroup was used to collect blood at 2
minutes and 2 hours. The second subgroup was used to collect blood at 24 hours and
4 days. The third subgroup was used to collect blood at 8 hours and 6 days.
[0172] The retro-orbital bleeds were collected through heparin-coated capillary tubes (Fisher
Scientific, Pittsburgh, PA) into K
2-EDTA coated tubes (BD Biosciences; San Jose, CA), placed on wet ice for approximately
30 minutes and then spun at 10,621 x g (10,000 rpm) in a microfuge for 8 minutes.
The second, terminal bleed, was collected through uncoated syringes into K
2-EDTA coated tubes (BD Biosciences) and then processed as above. Following centrifugation,
the plasma was removed and frozen at - 80°C until analyzed by ELISA.
[0173] For detection of R4Mut4 in plasma samples, a direct ELISA for FGF2 binding activity
was used. Briefly, Maxisorp 96-well plates (Nunc, Rochester, NY) were coated with
recombinant human FGF2 (PeproTech, Rocky Hill, NJ) in PBS (Mediatech, Herndon, VA)
at 1 ug/ml overnight at 4°C. The plates were then blocked with blocking buffer (1%
BSA (Sigma) in PBS) for 2-3 hours at room temperature. The plates were washed 6 times
with wash buffer (0.05% Tween-20 (v/v; Sigma) in PBS). Various dilutions of the test
samples and R4Mut4 standards were made with a constant final concentration of 5% plasma
in each sample. 100 ul of test sample was added to each well and then incubated for
approximately 90 minutes at room temperature. The plates were washed 6 times with
wash buffer, and then a peroxidase-conjugated AffiPure goat anti-human IgG-Fc antibody
(Jackson ImmunoResearch Laboratories, West Grove, PA) diluted at 1:60,000 in assay
diluent (1% BSA and 0.05% Tween-20 in PBS) was added to each well and incubated for
approximately 1 hour at room temperature. The plates were washed 6 times with wash
buffer. 100 ul per well of TMB substrate (Pierce Biotechnology, Chicago, IL) was then
added and incubated for 10 minutes. The reactions were quenched with 50 ul stop solution
(2 N H
2SO
4). The absorbance at 450 nm was then read on a SPECTRAmax PLUS microplate reader (Molecular
Devices, Sunnyvale, CA).
[0174] Results for all six time points from that experiment are shown in
Table 2 and the first 4 time points are shown graphically in
FIG. 4.
Table 2. R4Mut4 Serum Levels
| |
Average R4Mut4 serum plasma concentration +/- standard deviation (ng/ml) |
| Time point |
No Heparin |
With Heparin |
| 2 minutes |
5247 +/- 1367 |
44404 +/-7362 |
| 2 hours |
1329+/-236 |
6516 +/- 1293 |
| 8 hours |
628 +/- 138 |
592 +/- 109 |
| 1 day |
204 +/- 45 |
273 +/- 27 |
| 4 day |
Below limit of detection (156 ng/ml) |
Below limit of detection (156 ng/ml) |
| 6 day |
Below limit of detection (156 ng/ml) |
Below limit of detection (156 ng/ml) |
[0175] Those results demonstrate that co-administration of heparin with R4Mut4 increased
the maximum R4Mut4 concentration in the plasma (C
max) by approximately 9-fold over R4Mut4 administered alone at the 2 min time point and
approximately 7-fold at the 2 hour time point in that experiment. The two curves merge
at the 8 hour time point. These data show that heparin increases the amount of R4Mut4
that is free in the serum but that the protection was lost by 8 hours in that experiment.
Previous reports have shown that heparin has a short half-life
in vivo (∼45-60 minutes; see
Bjornsson and Levy, J. Pharmacol. Exp. Ther. (1979) 210:243-246) and this may play a role in the duration of the protective effect of heparin in
that experiment.
Example 7. FGFR ECD-Fc Binding to Extracellular Matrix Components In Vitro.
[0176] In vitro binding studies were conducted to characterize the ability of each of the four FGFR
ECD-Fc fusion proteins to bind to extracellular matrix components (ECM). For this
study, wild-type FGFR1 ECD-Fc, FGFR2 ECD-Fc, FGFR3 ECD-Fc and FGFR4 ECD-Fc fusion
proteins were purchased from R&D Systems (Minneapolis, MN).
[0177] 96-well Matrigel plates (Becton-Dickinson) were blocked with a 1% (w/v) solution
of BSA (Sigma). The FGFR ECD-Fc fusion proteins were serially diluted, transferred
to the Matrigel plates, and allowed to bind for 1 hour at room temperature. Unbound
fusion proteins were removed by washing three times with PBS (EMD Biosciences; La
Jolla, CA) and 0.5% Tween (v/v; Sigma). Bound fusion proteins were detected using
a peroxidase-conjugated anti-human Fc antibody (Bethel Laboratories, Montgomery, TX)
and OPD (o-phenylenediamine dihydrochloride) substrate (Sigma), according to the manufacturer's
instructions. FGFR4 ECD-Fc bound tightly to the Matrigel plates with an EC
50 of approximately 300 ng/mL in that experiment.
See FIG. 5. FGFR1 ECD-Fc, FGFR2 ECD-Fc, and FGFR3 ECD-Fc all showed significantly weaker binding
to the Matrigel plates than the FGFR4 ECD-Fc, with half-maximal binding not observed
in that experiment even at concentrations of 10,000 ng/ml.
See FIG. 5.
Example 8. FGFR4 ECD Acidic Region Chimera-Fc Fusion Proteins Bind to FGF2 and FGF19.
[0178] In order to reduce tissue binding and improve the pharmacokinetic profile, three
FGFR4 ECD acidic region chimeras were fused to Fc, expressed in 293-6E cells, and
purified. In addition, two FGFR4 2Ig ECD-Fc fusion proteins in which D1 or D1 + the
acid box region were deleted, were constructed, expressed, and purified.
[0179] The FGF2 and FGF19 ligand binding affinity and kinetics of the parental R4Mut4 and
the five different FGFR4 ECD-Fc fusion proteins (collectively "the R4 proteins") were
determined using Biacore
® X surface plasmon resonance (SPR) technology (Uppsala, Sweden). FGF2 was selected
because it is broadly expressed in adult tissue and has been implicated in cancer
progression and angiogenesis. FGF19 was selected because, in the absence of other
protein cofactors, it binds specifically to FGFR4. Briefly, Protein-A was covalently
linked to a CM5 chip, according to manufacturer's instructions. The R4 proteins were
produced in 293-6E host cells as described in Example 2, purified as described in
Example 3, and then bound to the chip by interaction of the Fc domain with Protein-A.
The R4 proteins were captured onto flow channels 2-4, while channel 1 served as a
reference. FGF2 was purchased from Peprotech (Rocky Hill, NJ) and FGF19 was purchased
from R&D Systems. Each FGF ligand was injected at 5 concentrations (100 nM, 25 nM,
6.25 nM, 1.56 nM, and 0 nM) for 2 minutes and dissociation was monitored for 4 minutes.
50 uM Heparin was included in the running buffer. The association constant, dissociation
constant, affinity, and binding capacity of each of the R4 proteins for FGF2 and FGF19
was calculated using the Biacore T100 Evaluation software package using the 1:1 binding
model.
[0180] The results of that experiment are shown in
Tables 3 and 4.
Table 3. FGF2 Ligand Binding
| Protein Name |
ka (1/M·ms) |
kd (1/s)·1000 |
KD (nM) |
Rmax (RU) |
| R4Mut4 (experiment 1) |
59 |
0.23 |
3.90 |
46 |
| R4Mut4 (experiment 2) |
45 |
0.27 |
5.88 |
53 |
| ABMut1 |
160 |
0.27 |
1.70 |
56 |
| ABMut2 |
114 |
0.26 |
2.26 |
57 |
| ABMut3 |
242 |
0.35 |
1.44 |
58 |
| R4(2Ig+L) |
313 |
0.79 |
2.54 |
62 |
| R4(2Ig-L) |
306 |
0.73 |
2.40 |
51 |
Table 4. FGF19 Ligand Binding
| Protein Name |
ka (1/M·ms) |
kd (1/s)·1000 |
KD (nM) |
Rmax (RU) |
| R4Mut4 (experiment 1) |
176 |
0.63 |
3.60 |
55 |
| R4Mut4 (experiment 2) |
184 |
0.61 |
3.32 |
50 |
| ABMut1 |
213 |
0.68 |
3.18 |
45 |
| ABMut2 |
250 |
0.64 |
2.58 |
44 |
| ABMut3 |
211 |
0.74 |
3.50 |
40 |
| R4(2Ig+L) |
80 |
2.76 |
34.31 |
26 |
| R4(2Ig-L) |
118 |
2.14 |
18.15 |
18 |
[0181] As shown in
Tables 3 and 4, the three chimeras ABMut1, ABMut2, and ABMut3, had an affinity equal to or greater
than the parental R4Mut4 for both FGF2 and FGF19 in that experiment, as measured by
the equilibrium dissociation constant (K
D).
[0182] In addition, FGFR4 ECD-Fc fusion proteins in which D1 was deleted, in either the
presence (R4(2Ig+L)) or absence (R4(2Ig-L)) of the D1-D2 linker region, bound FGF2
with an affinity equal to or greater than the parental R4Mut4 in that experiment,
as measured by the equilibrium dissociation constant (K
D). Deletion of D1 reduced binding to FGF19 by approximately ten-fold in the presence
of the D1-D2 linker region (R4(2Ig+L)), and by approximately five-fold in the absence
of the D1-D2 linker region (R4(2Ig-L)) in that experiment.
[0183] Those results show that all of the R4 proteins tested retained the ability to bind
to FGFR2 and/or FGF19, although the D1 deletion proteins exhibited weaker binding
to FGF19 than the parental or the acidic region chimeras in that experiment.
Example 9. FGFR4 ECD Acidic Region Chimera-Fc Fusion Protein Binding to Extracellular
Matrix (ECM) Components In Vitro.
[0184] In vitro binding studies were conducted to characterize the ability of the FGFR4 ECD acidic
region chimeras to bind to ECM. FGFR4-Fc acidic region chimera-Fc fusion proteins
were expressed in 293-6E cells, as described in Example 2, and all were purified as
described in Example 3. The parental R4Mut4 was expressed in CHO cells as described
in Example 2 and also purified as described in Example 3.
[0185] Binding experiments were performed as described in Example 7, and a graphical representation
of the results is shown in
FIG. 6. In this experiment, the parental R4Mut4 bound to Matrigel plates with an EC
50 of approximately 100 ng/ml. All three FGFR ECD acidic region chimera-Fc fusion proteins
showed minimal binding to Matrigel plates up to a concentration of 10,000 ng/ml in
that experiment. Therefore, the substitution of the FGFR1 D1-D2 linker, FGFR1 exon
4, or FGFR1 acid box region for the corresponding region of the FGFR4 ECD abrogated
the
in vitro extracellular matrix binding of the FGFR4 ECD in that experiment.
Example 10. FGFR4 ECD Acidic Region Chimera-Fc Fusion Protein Binding to Hepatocytes
In Vitro.
[0186] FGFR4 ECD acidic region chimera-Fc fusion proteins ABMut1, ABMut2 and ABMut3 were
tested for their ability to bind hepatocytes. The fusion proteins were expressed in
293-6E cells, as described in Example 2, and purified as described in Example 3. The
R1Mut4 and R4Mut4 proteins were expressed in CHO-S cells, as described in Example
2, and purified as described in Example 3. Human IgG1 control protein was obtained
from Caltag.
[0187] The hepatocyte binding experiments were performed as described in Example 5 and a
graphical representation of the results is shown in
FIG. 7. In that experiment, all three FGFR4 ECD acidic region chimera-Fc fusion proteins
showed hepatocyte binding that was equivalent to R1Mut4, and was greatly reduced compared
to the parental R4Mut4.
Example 11. Pharmacokinetics of an FGFR4 ECD Acidic Region Chimera-Fc Fusion Protein
in Mice.
[0188] The pharmacokinetic properties of ABMut1 were compared to the parental R4Mut4
in vivo. Both proteins were expressed in CHO-S cells as described in Example 2 and purified
as described in Example 3.
[0189] Forty female Balb/C mice (Charles River Laboratories, Wilmington, MA) were weighed
and sorted into two groups of 20 mice based on a random distribution of body weight.
Mice in the first group received R4Mut4 and mice in the second group received ABMut1.
Each mouse received 5 mg protein per kilogram body weight via intravenous injection
through the tail vein in a total volume of 0.2 ml PBS (Cellgro).
[0190] Blood plasma was collected at 9 different time points following IV administration,
at approximately 2 minutes, 30 minutes, 2 hours, 7 hours, 1 day, 2 days, 3 days, 5
days, and 7 days. Blood was collected from each mouse two or three times, the first
one or two collections by a retro-orbital bleed and the last terminally by cardiac
puncture. The 20 mice from each treatment group were further divided into four subgroups
of 5 mice. Each group was bled at the times shown in
Table 5.
Table 5. Sample Collection Times and Methods
| |
Time points of blood collection (following IV administration) |
| Group (n = 5) |
Retro-orbital bleed |
Terminal cardiac puncture |
| Group 1 |
2 and 5 minutes |
7 days |
| Group 2 |
30 minutes |
7 hours |
| Group 3 |
2 hours |
24 hours |
| Group 4 |
2 days |
3 days |
[0191] Plasma serum was collected and the R4Mut4 and ABMut1 protein levels determined by
a direct FGF2 binding ELISA as described in Example 7. The results are shown in
FIG. 8 and certain pharmacokinetic parameters are given in
Table 6. The results show that the replacement of the D1-D2 linker of the FGFR4 ECD with the
FGFR1 D1-D2 linker increased the half-life (t
1/2) of the administered protein by 126%, increased the maximum observed plasma concentration
(C
max) by 183%, and increased the clearance time (CL) by 302%. The improved pharmacokinetic
profile of ABMut1 shows that it is present in the blood, at a therapeutic concentration,
longer than the parental R4Mut4 molecule.
Table 6. Pharmacokinetic Parameters of R4Mut4 and ABMut1
| Protein |
t1/2 (in hours) |
Cmax (in ug/ml) |
CL (in ml/hr/kg) |
| R4Mut4 |
15.7 |
18.7 |
23.6 |
| ABMut1 |
35.5 |
52.9 |
94.8 |
| Change (%) |
126% |
183% |
302% |
Example 12. Activity in HCT116sc Cancer Xenograft Model.
[0192] The anti-cancer activities of the parental R4Mut4 and ABMut1 were tested in a xenograft
colon cancer model using human colon carcinoma HCT116sc cells. The HCT116sc cell line
is a sub-line of the HCT116 colon carcinoma cell line (ATCC, Manassas, VA) isolated
from a subcutaneous HCT116 tumor and selected for more consistent
in vivo growth using standard cell culture and xenograft techniques. To prepare the HCT116sc
cells for the xenograft experiment, the cells were cultured for five passages in RPMI
1640 media supplemented with 10% FBS (vol/vol), 2 mM L-Glutamine, 100 IU/ml of penicillin
and 100 ug/ml of streptomycin (all from Cellgro) at 37°C in a humidified atmosphere
with 5% CO
2. Semi-confluent cells (∼80%) were re-suspended in PBS without calcium and magnesium
(Cellgro) at a concentration of 1x10
8 cells per ml. Matrigel basement membrane matrix (BD Biosciences) was added to 50%
(vol/vol) to give a final concentration of 5x10
7 cells per ml and the mixture stored on ice until implantation into mice.
[0193] For the xenograft experiments, sixty CB17 SCID mice (Charles River Laboratories)
were used. On day 1, the body weight of each mouse was measured. The mice were randomly
distributed into 6 groups of 10 mice based on their body weight. Once assigned to
a treatment group, the mice were shaved on the right hind flank and then inoculated
subcutaneously with 5x10
6 (100 ul) of the HCT116sc cells prepared as described above.
[0194] On the next day, animals were dosed with the test articles according to the dosing
scheme shown in
Table 7. R4Mut4 and ABMut1 were expressed in CHO-S cells and purified as described in
Examples 2 and 3, respectively.
Table 7. HCT116sc Xenograft Dosing Groups
| Group |
Number of Animals |
Test Article and Dose (mg test article per weight mouse) |
Dosing Route and Schedule |
| 1 |
10 |
Vehicle |
Intravenous, 2X/week |
| 2 |
10 |
R4Mut4,20 mg/kg |
Intraperitoneal, daily |
| 3 |
10 |
R4Mut4, 10 mg/kg |
Intravenous, 2X/week |
| 4 |
10 |
R4Mut4, 20 mg/kg |
Intravenous, 2X/week |
| 5 |
10 |
ABMut1, 10 mg/kg |
Intravenous, 2X/week |
| 6 |
10 |
ABMut1, 20 mg/kg |
Intravenous, 2X/week |
[0195] Tumor sizes were measured in each mouse on days 7, 14, and 21 following the day of
tumor cell inoculation. The length and width of each tumor was measured using calipers
and the tumor size calculated according to the formula:

[0196] FIG. 9 shows the results of that experiment. All groups of mice that received R4Mut4 or
ABMut1 showed a diminution of tumor growth compared to vehicle-treated animals. Table
8 shows the average percent inhibition of tumor growth for each treatment group at
days 14 and 21 compared to the vehicle treated group, and the corresponding p-values.
P-values were calculated using an ANOVA analysis followed by the Bonferonni t-test.
See, e.g., Mathematical Statistics and Data Analysis, 1988, Wadsworth & Brooks, Pacific Grove,
CA. This analysis demonstrated that ABMut1 reduced tumor growth to a similar or greater
extent than the parental R4Mut4 in that experiment.
Table 8. HCT116sc Xenograft Results
| Group |
Day 14: Percent inhibition; p-value |
Day 21: Percent inhibition; p-value |
| R4Mut4, 20 mg/kg, IP |
43%, p-value = 0.003 |
33%, p-value = 0.014 |
| R4Mut4, 10 mg/kg, IV |
42%; p-value = 0.003 |
27%; p-value = 0.068 |
| R4Mut4, 20 mg/kg, IV |
37%; p-value = 0.011 |
21%; p-value = 0.083 |
| ABMut1, 10 mg/kg, IV |
42%; p-value = 0.003 |
29%; p-value = 0.015 |
| ABMut1, 20 mg/kg, IV |
52%; p-value = 0.002 |
40%; p-value = 0.003 |
Example 13. Increasing the Concentration of an FGFR4 ECD Acidic Region Chimera Leads
to Detectable ECM Binding In Vitro.
[0197] As described in
Example 9 and shown in
FIG. 6, early
in vitro binding experiments showed minimal binding of three FGFR4 ECD acidic region chimera-Fc
fusion proteins (ABMut1, ABMut2, and ABMut3) to ECM components when up to 10,000 ng/ml
of purified protein was incubated with Matrigel plates. Experiments were carried out
to determine whether higher concentrations (up to 1 mg/ml) of the ABMut1 fusion protein
could exhibit increased levels of ECM binding in the same
in vitro ECM binding assay.
[0198] In these experiments, the R1Mut4, R4Mut4, and ABMut1 fusion proteins were used. The
R1Mut4 fusion protein served as a negative control for ECM binding (data not shown),
and the R4Mut4 fusion protein served as a positive control for ECM binding. All three
fusion proteins were expressed in CHO cells as described in
Example 2 and purified as described in
Example 3. The R4Mut4 and ABMut1 fusion proteins were also transiently expressed in 293-T cells.
For transient expression in 293-T cells, 0.5-0.65 x 10
6 cells were plated in each well of a 6-well plate (with or without poly-lysine coating)
in 2 ml DMEM supplemented with 10% FBS. A Fugene™ (Roche) stock was made by combining
93.5 ul Optimem with 6.5 ul Fugene™, followed by a 5 min incubation. A DNA stock was
made by combining 1.3 ug DNA with Optimem to a final volume of 100 ul. The Fugene™
stock (100 ul) was added to the DNA stock (100 ul), and the combined solution (200
ul) was added to one well of the 6-well plate. The solution was gently swirled and
allowed to incubate with the cells for 30 min at room temperature. The cells were
incubated in a humidified incubator with 5% CO
2. After 40 hours, the medium was removed, the cells were washed, and 1.5 ml Optimem
was added to each well. Forty-nine hours after the medium was changed, the supernatant
was collected, spun at 1,400 rpm for 10 min, and transferred to a fresh tube. The
fusion proteins were purified from the culture medium as described in
Example 3, except that only the first purification step of Protein-A affinity chromatography
was used. Protein levels were determined using AlphaScreen (hu IgG AlphaLISA; Perkin-Elmer
#AL205C). ECM binding experiments were carried out as described in
Example 7, except that up to 1 mg/ml of each FGFR ECD-Fc fusion protein was used in the
in vitro ECM binding assay. A graphical representation of the results is shown in
FIG. 12. As shown in
FIG. 12, detectable levels of ECM binding were observed for the ABMut1 fusion protein at higher
concentrations, although ECM binding by the ABMut1 fusion protein was still much lower
than that of the R4Mut4 fusion protein.
Example 14. Replacement of Certain Individual Non-Acidic Residues in the FGFR4 ECD
Long Acid Box with the Corresponding Acidic Residues from FGFR1 is Not Sufficient
to Inhibit ECM Binding In Vitro.
[0199] Experiments were carried out to determine whether the replacement of individual non-acidic
residues in the FGFR4 ECD long acid box with the corresponding acidic residues from
FGFR1 could inhibit ECM binding
in vitro. This experiment used four FGFR4 ECD long acid box variants in which a single non-acidic
residue from the FGFR4 ECD of R4Mut4 was replaced with the corresponding acidic residue
from FGFR1. Conventional cloning and site-directed mutagenesis methods were employed
to generate clones in the pTT5 vector encoding the R4Mut4(N104D), R4Mut4(P109D), R4Mut4(R113E),
and R4Mut4(S116E) fusion proteins. The R4Mut4(N104D), R4Mut4(P109D), R4Mut4(R113E),
and R4Mut4(S116E) long acid box variants correspond to SEQ ID NOs: 130, 131, 132,
and 133, respectively. The R4Mut4(N104D), R4Mut4(P109D), R4Mut4(R113E), and R4Mut4(S116E)
variants each contained a single amino acid change at amino acids 104, 109, 113, and
116, respectively, in SEQ ID NOs: 1 and 2.
In vitro ECM binding of the four FGFR4 ECD long acid box variants with single amino acid substitutions
was compared to the R1Mut4, R4Mut4, and ABMut1 fusion proteins.
[0200] All of the fusion proteins, including R1Mut4, R4Mut4, ABMut1, R4Mut4(N104D), R4Mut4(P109D),
R4Mut4(R113E), andR4Mut4(S116E) were transiently expressed in 293-T cells and purified
as described in
Example 1. Protein levels were determined using AlphaScreen (hu IgG AlphaLISA; Perkin-Elmer
#AL205C). The concentrations of purified R4Mut4(N104D) and R4Mut4(S116E) were too
low to reliably determine ECM binding. The concentrations of the purified R4Mut4(P109D)
and R4Mut4(R113E) fusion proteins were lower than the concentrations of the purified
R1Mut4, R4Mut4, and ABMut1 fusion proteins, and did not permit an analysis of their
ECM binding at the highest concentrations. ECM binding experiments were carried out
as described in
Example 7, except that higher protein levels were used for most of the fusion proteins tested
in the
in vitro ECM binding assay. A graphical representation of the results is shown in
FIG. 13. As shown in
FIG. 13, the R4Mut4 variants with single amino acid substitutions that were expressed at sufficient
levels to determine ECM binding (i.e., the R4Mut4(P109D) and R4Mut4(R113E)) did not
exhibit decreased ECM binding relative to R4Mut4.
Example 15. FGFR4 ECD Long Acid Box Variants that Contain at Least Two Additional
Acidic Residues Exhibit Decreased ECM Binding.
[0201] Experiments described in
Example 14 showed that increasing the total number of acidic amino acid residues in the long
acid box of an FGFR4 ECD acidic region mutein by one was not sufficient to inhibit
ECM binding
in vitro. Thus, experiments were carried out to determine whether a further increase in the
number of acidic amino acid residues in the long acid box of an FGFR4 ECD acidic region
mutein, including any acidic amino acid residues inserted between amino acids 103
and 104 of SEQ ID NOs: 1 and 2, could inhibit ECM binding
in vitro.
[0202] Five FGFR4 ECD long acid box variant fusion molecules, called R4(104-114):R1(106-117),
R4(104-114):R1(107-117), R4(104-110):R1(105-113), R4(113-116):R1(116-119), and R4(109-113):R1(112-116),
corresponding to SEQ. ID. NOs: 134, 135, 136, 137, and 138, respectively, were used
in these experiments. In the R4(104-114):R1(106-117) FGFR4 ECD long acid box variant,
amino acids 106 to 117 of the FGFR1 ECD replace amino acids 104 to 114 of the FGFR4
ECD. In the R4(104-114):R1(107-117) FGFR4 ECD long acid box variant, amino acids 107
to 117 of the FGFR1 ECD replace amino acids 104 to 114 of the FGFR4 ECD. In the R4(104-110):R1(105-113)
FGFR4 ECD long acid box variant, amino acids 105 to 113 of the FGFR1 ECD replace amino
acids 104 to 110 of the FGFR4 ECD. In the R4(113-116):R1(116-119) FGFR4 ECD long acid
box variant, amino acids 116 to 119 of the FGFR1 ECD replace amino acids 113 to 116
of the FGFR4 ECD. In the R4(109-113):R1(112-116) FGFR4 ECD long acid box variant,
amino acids 112 to 116 of the FGFR1 ECD replace amino acids 109 to 113 of the FGFR4
ECD. Conventional cloning and site-directed mutagenesis were employed to generate
clones in the pTT5 vector encoding the R4(104-114):R1(106-117), R4(104-114):R1(107-117),
R4(104-110):R1(105-113), R4(113-116):R1(116-119), and R4(109-113):R1(112-116) fusion
proteins using the R4Mut4 parental clone as a template.
In vitro ECM binding of the four FGFR4 ECD long acid box variants was compared to the R1Mut4,
R4Mut4, and ABMut1 fusion proteins.
[0203] All of the fusion proteins, including R1Mut4, R4Mut4, ABMut1, R4(104-114):R1(106-117),
R4(104-114):R1(107-117), R4(104-110):R1(105-113), R4(113-116):R1(116-119), and R4(109-113):R1(112-116)
were transiently expressed in 293-T cells and purified as described in
Example 11. Protein levels were determined using AlphaScreen (hu IgG AlphaLISA; Perkin-Elmer
#AL205C). ECM binding experiments were carried out as described in
Example 7, except that up to 1 mg/ml of the FGFR ECD-Fc fusion proteins were used in the
in vitro ECM binding assay. A graphical representation of the results is shown in
FIG. 14. As shown in
FIG. 14, at least the R4(104-114):R1(106-117) and R4(104-110):R1(105-113) FGFR4 ECD long acid
box variants exhibited ECM binding levels that were intermediate between the R4Mut4
and ABMut1 fusion proteins.
Example 16. FGFR4 ECD Acidic Region Chimeras Lacking Individual N-Glycan Sites Exhibit
Decreased ECM Binding.
[0204] The FGFR4 ECD contains five N-glycan sites as determined by mass spectrometry. (Data
not shown.) The FGFR4 ECD N-glycan sites at amino acids N91 and N156 of SEQ. ID. NOs:
1 and 2 are located adjacent to the amino-terminus of the FGFR4 D1-D2 linker and in
the D2 heparin binding domain, respectively. In the ABMut1 FGFR4 ECD D1-1D2 linker
chimera of SEQ ID NO: 25, those N-glycan sites are located at amino acids N91 and
N159. Experiments were carried out to determine whether the introduction of either
the N91A or the N159A N-glycan mutation could further reduce the
in vitro ECM binding of the ABMut1 fusion protein. Conventional cloning and site-directed
mutagenesis methods were employed to generate clones in the pTT5 vector encoding the
ABMut1 fusion protein with the N91A or the N159A N-glycan mutation, referred to herein
as ABMut1(N91A) and ABMut1(N159A), respectively. ABMut1(N91A) and ABMut1(N159A) fusion
proteins correspond to SEQ ID NOs: 139 and 140, respectively.
[0205] The R4Mut4, ABMut1, ABMut1(N91A), and ABMut1(N159A) fusion proteins were used in
these experiments. All four fusion proteins were transiently expressed in CHO-S cells.
Briefly, a 500 ml culture of CHO-S cells (Invitrogen) was established by inoculating
0.5 x 10
6 cells/ml in fresh 37°C Freestyle CHO medium containing 8 mM L-Glutamine (Invitrogen).
The cells were grown in a 2 1 plastic flask and were derived from a seed strain that
was continuously maintained up to passage 20. The following day, the cells were counted
and diluted, if necessary, to 1 x 10
6 cells/ml in 37°C Freestyle CHO medium (Invitrogen) with a cell viability greater
than 95%. The cells were transfected by transferring 10 ml of 37°C OptiPRO SFM medium
containing 8 mM L-Glutamine (dilution media) into two 50 ml tubes. To the first tube
(A), 625 ul of FreestyleMax transfection reagent (Invitrogen) were added. To the second
tube (B), 625 ug of DNA were added. Both tubes were gently mixed by inverting, and
the contents of tube A were immediately added to tube B, followed by gentle mixing
by inversion. The mixture was incubated at room temperature for between 10 to 20 min,
and was then delivered drop-wise into the 500 ml cell culture in the 2 1 culture flask
while slowly swirling the flask. The culture was then transferred to an incubator
at 37°C, 5% CO
2, 125 rpm. After six days, the cell viability was greater than 80%, and the culture
supernatant was collected into a centrifuge bottle. The supernatant was centrifuged
at 1,000 xg for 10 min, transferred to a new centrifuge bottle, and centrifuged at
4,000 xg for 10 min. The supernatant was collected into a new bottle and filtered
through a 0.2 um filter. The supernatant was stored at 37°C prior to the purification
step. The fusion proteins were purified from the culture supernatant as described
in
Example 3, except that Q Sepharose anion exchange chromatography was used as the second purification
step. Protein-A eluates were applied to a Q Sepharose HP column (GE Healthcare 17-1014-01)
equilibrated with five column volumes of sterile buffer (10 mM Tris, 50 mM NaCl, pH
8.0). The column was washed with five column volumes of the same buffer and the bound
material was eluted at a rate of five ml/min with a linear gradient of 15 column volumes
of elution buffer (10 mM Tris, 2 M NaCl, pH 8.0), followed by five column volumes
with 100% elution buffer. Fourteen ml fractions were collected and the fractions comprising
the FGFR ECD-Fc were identified by gel electrophoresis and pooled. FGFR ECD-Fc fusion
proteins eluted with approximately 10-25% elution buffer.
[0206] Protein levels were determined based on absorbance measurements at 280 nm. ECM binding
experiments were carried out as described in
Example 7, except that up to 1 mg/ml of the fusion proteins was used in the
in vitro ECM binding assay. A graphical representation of the results is shown in
FIG. 15. As shown in
FIG. 15, the ABMut1 fusion protein with either the N91A or the N159A N-glycan mutation exhibited
a further decrease in
in vitro ECM binding, which would also predict a further increase in both C
max and bioavailability.
[0207] An FGF2 competition ELISA assay was carried out to determine whether the ABMut1(N91A)
and ABMut1(N159A) fusion proteins could inhibit the binding of FGF2 or FGF19 to surface-bound
FGFR4 ECD-Fc (R4Mut4). In these assays, ABMut1 was the reference standard, and ABMut1(N91A)
and ABMut1(N159A) were the test samples. Purified ABMut1, ABMut1(N91A), and ABMut1(N159A)
were serially diluted in sample diluent (PBS containing 1% BSA (fraction V; Sigma
#A3059), 0.05% Tween-20, 200 ng/ml FGF2 (PreproTech #100-18B) or 50 ng/ml FGF19 (PeproTech
#100-32), and 20 ug/ml heparin (Sigma #H3149)) to concentrations ranging from 1.5
ng/ml to 90,000 ng/ml. The protein mixtures were incubated for 60 min. A 96-well plate
was incubated with 100 ul of 5 ug/ml R4Mut4 overnight at 4°C, washed three times,
blocked in blocking buffer (PBS containing 1% BSA) for between one and two hours at
room temperature, and washed three times. The protein mixtures (100 ul) were then
transferred to the wells of the 96-well plate and incubated for one hour at room temperature
with shaking.
[0208] In this assay, FGF2 or FGF19 that was not bound to the test samples or the reference
standard during the initial incubation step would be free to bind to the surface-bound
R4Mut4. The wells were washed three times using a plate washer, followed by detection
using biotinylated anti-FGF2 antibody (R&D Systems #BAM233) or biotinylated anti-FGF19
antibody (R&D Systems #BAF969) with the VECTASTAIN ABC Kit (Vector Laboratories #PK-4000).
Biotinylated anti-FGF2 antibody or biotinylated anti-FGF19 was diluted to 1 ug/ml
in assay diluent (PBS containing 1% BSA and 0.05% Tween-20), and 100 ul was added
to each well, followed by a one hour incubation at room temperature with shaking.
The ABC solution was reconstituted by mixing three drops of solution A with three
drops of solution B in 15 ml PBS, and the solution was allowed to stand for 30 min
at room temperature. The plates were washed six times using a plate washer and 100
ul of the freshly reconstituted ABC solution were added to each well, followed by
a 45 min to one hour incubation at room temperature. TMB substrate (100 ul) was added
to each well, followed by incubation for 6 to 8 min at room temperature in the dark
with gentle shaking. One hundred microliters of stop solution were added to each well,
and the plates were mixed by tapping. The plate optical density (OD) was read at 450
nm with 570 nm subtraction.
[0209] The OD values were then plotted versus the protein concentration on a log scale to
generate standard curves. The OD value for each well was directly proportional to
the amount of bound FGF2 or FGF19, and was inversely proportional to the amount of
active FGFR4 ECD-Fc fusion protein in the test solution. The concentration profiles
for the test samples and the reference standards were fit using a 4-parameter logistic.
The relative binding activity (% bioactivity) of each test sample was calculated by
dividing the IC
50 value for the standard reference by the IC
50 value for the test sample, which was then multiplied by 100%. The relative FGF2 binding
activities of ABMut1(N91A) and ABMut1(N159A) in this assay were 44% and 42%, respectively.
The relative FGF19 binding activities of ABMut1(N91A) and ABMut1(N159A) in this assay
were 51% and 56%, respectively.
Example 17. FGFR4 ECD D1-D2 Linker Chimeras with the FGFR2 or FGFR3 D1-D2 Linker Exhibit
Decreased ECM Binding In Vitro.
[0210] Experiments were carried out to determine whether FGFR4 ECD D1-D2 linker chimeras
in which the FGFR4 D1-D2 linker was replaced with either the FGFR2 D1-D2 linker ("R4(D1-D2):R2(D1-D2)")
or the FGFR3 D1-D2 linker ("R4(D1-D2):R3(D1-D2)") exhibited decreased binding to ECM
components
in vitro. Both the FGFR2 D1-D2 linker and the FGFR3 D1-D2 linker contain more acidic residues
than the FGFR4 D1-D2 linker. Conventional cloning techniques were employed to generate
clones in the pTT5 vector encoding the R4(D1-D2):R2(D1-D2) and R4(D1-D2):R3(D1-D2)
fusion proteins. R4(D1-D2):R2(D1-D2) and R4(D1-D2):R3(D1-D2) correspond to SEQ ID
NOs: 143 and 144, respectively.
[0211] The R1Mut4, R4Mut4, ABMut1, R4(D1-D2):R2(D1-D2), and R4(D1-D2):R3(D1-D2) fusion proteins
were used in these experiments. All of the fusion proteins were expressed in 293-T
cells as described in
Example 11. Protein levels were determined using AlphaScreen (hu IgG AlphaLISA; Perkin-Elmer
#AL205C). The concentration of the purified R4(D1-D2):R3(D1-D2) fusion protein was
lower than the concentrations of the purified R1Mut4, R4Mut4, ABMut1, and R4(D1-D2):R2(D1-D2)
fusion proteins, and did not permit an analysis of its ECM binding at higher concentrations.
ECM binding experiments were carried out as described in
Example 7, except that up to nearly 1 mg/ml of the FGFR ECD-Fc fusion proteins were used in
the
in vitro ECM binding assay. A graphical representation of the results is shown in
FIG. 16. As shown in
FIG. 16, both the R4(D1-D2):R2(D1-D2) and R4(D1-D2):R3(D1-D2) fusion proteins exhibited ECM
binding levels similar to that of the ABMut1 fusion protein.
Example 18. FGFR2 and FGFR3 Short Acid Box Chimeras with the FGFR1 Short Acid Box
Exhibit Decreased ECM Binding In Vitro.
[0212] Experiments were carried out to determine whether an increase in the total number
of acidic residues within the long acid box of FGFR2 and FGFR3 could further decrease
their ECM binding
in vitro. FGFR2 and FGFR3 short acid box chimeras were generated in which the amino acid residues
of the short acid box of FGFR1 replaced the corresponding amino acid residues within
the FGFR2 and FGFR3 long acid box, referred to as R2(111-118):R1(105-112) and R3(110-117):R1(105-112),
respectively. Conventional cloning techniques were employed to generate clones in
the pTT5 vector encoding the R2(111-118):R1(105-112) and R3(110-117):R1(105-112) fusion
proteins. R2(111-118):R1(105-112) and R3(110-117):R1(105-112) correspond to SEQ ID
NOs: 166 and 167, respectively.
[0213] The FGFR2 ECD-Fc, FGFR3 ECD-Fc, R2(111-118):R1(105-112), and R3(110-117):R1(105-112)
fusion proteins were used in these experiments. The FGFR2 ECD-Fc, FGFR3 ECD-Fc fusion
proteins, R2(111-118):R1(105-112), and R3(110-117):R1(105-112) fusion proteins were
transiently expressed in CHO-S cells and purified as described in
Example 16. Protein levels were determined using absorbance measurements at 280 nm. ECM binding
experiments were carried out as described in
Example 7, except that up to 1 mg/ml of each fusion protein was used in the
in vitro ECM binding assays. Graphical representations of the results are shown in
FIGs. 17A-B. As shown in
FIG. 17A and
FIG. 17B, the R2(111-118):R1(105-112) and R3(110-117):R1(105-112) fusion proteins exhibited
slightly less ECM binding
in vitro relative to the FGFR2 ECD-Fc and FGFR3 ECD-Fc fusion proteins, respectively.
INDUSTRIAL APPLICABILITY
[0214] The FGFR ECD acidic region muteins and the FGFR ECD fusion molecules described herein
are useful in treating proliferative diseases and diseases involving angiogenesis,
including cancer and macular degeneration. They can be used to diagnose, prevent,
and treat these diseases.
TABLE OF SEQUENCES
SEQUENCE LISTING
[0216]
<110> Marshall, Shannon
Charych, Deborah H.
Sadra, Ali
<120> FGFR Extracellular Domain Acidic Region Muteins
<130> 08940.0071
<150> US 60/086,121
<151> 2008-08-04
<160> 173
<170> PatentIn version 3.5
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<223> Synthetic sequence
<400> 167



<210> 168
<211> 334
<212> PRT
<213> Artificial Sequence
<220>
<223> Synthetic sequence
<400> 168



<210> 169
<211> 566
<212> PRT
<213> Artificial Sequence
<220>
<223> Synthetic sequence
<400> 169



<210> 170
<211> 229
<212> PRT
<213> Artificial Sequence
<220>
<223> Synthetic sequence
<400> 170


<210> 171
<211> 228
<212> PRT
<213> Artificial Sequence
<220>
<223> Synthetic sequence
<400> 171


<210> 172
<211> 339
<212> PRT
<213> Artificial Sequence
<220>
<223> Synthetic sequence
<400> 172


<210> 173
<211> 374
<212> PRT
<213> Artificial Sequence
<220>
<223> Synthetic sequence
<400> 173


